{"gene":"PF3D7_1446200","run_date":"2026-09-08T14:19:07","timeline":{"discoveries":[{"year":2006,"finding":"LAP (PF3D7_1446200) was expressed in insect cells as a functionally active 320-kDa homo-hexamer that is optimally active at neutral or alkaline pH, is dependent on metal ions for activity, and exhibits substrate preference for N-terminally exposed hydrophobic amino acids, particularly leucine.","method":"Recombinant expression in insect cells, biochemical characterization (enzymatic assay, size determination)","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstitution of recombinant enzyme with enzymatic assay, substrate profiling, and oligomeric characterization; replicated by multiple subsequent studies","pmids":["17107951"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2006,"finding":"LAP (PF3D7_1446200) is localized to the cytosolic compartment of the parasite at all intra-erythrocytic developmental stages, including segregated merozoites, as determined by immunohistochemistry and transfection with a LAP-GFP fusion construct.","method":"Immunofluorescence microscopy, GFP-fusion transfection and live imaging","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct localization by two orthogonal methods (IHC and GFP-fusion live imaging), replicated in subsequent studies","pmids":["17107951","16286469","33536500"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2005,"finding":"Transgenic P. falciparum parasites overexpressing LAP (PF3D7_1446200) showed twice the leucyl aminopeptidase activity in cytosolic extracts and were more resistant to bestatin (EC50 64 µM vs. 25 µM in wild-type), demonstrating that LAP is the functional target of bestatin's antimalarial activity.","method":"Parasite transfection (overexpression), enzymatic activity assay on cytosolic extracts, in vitro inhibitor sensitivity assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic overexpression with matched enzymatic and pharmacological readouts; target validation by gain-of-function resistance","pmids":["16286469"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2009,"finding":"The active site of LAP (PF3D7_1446200) contains two metal-binding sites: a readily exchangeable site 1 and a tight-binding site 2. Removal of metal from site 1 alone retains activity; removal from both sites yields an inactive apoenzyme that cannot be reactivated. Site 1 shows preference for Zn2+ > Mn2+ > Co2+ > Mg2+, and the identity of the metal at site 1 influences both catalytic efficiency and the binding mode of the inhibitor bestatin.","method":"Metal chelation/reconstitution of recombinant enzyme, enzyme kinetics, inhibitor binding studies","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro biochemical reconstitution with metal manipulation and kinetic analysis; single lab but multiple orthogonal methods","pmids":["19408962"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2010,"finding":"X-ray crystal structure of LAP (PF3D7_1446200) as a hexamer was solved, revealing that the six active sites are arranged in a disc-like fashion oriented inward to form a central catalytic cavity, with flexible loops at each of the six entrances regulating substrate access. The structure shows a narrow, hydrophobic primary specificity pocket accounting for its restricted substrate specificity, and two metal-binding centers per active site important for substrate and inhibitor binding.","method":"X-ray crystallography (apo and inhibitor-bound structures)","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure with inhibitor-bound complexes, multiple structures; replicated in subsequent structural studies","pmids":["20133789"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2011,"finding":"Specific inhibition of LAP (PF3D7_1446200) using a selective activity-based probe was lethal to P. falciparum parasites early in the intra-erythrocytic life cycle, prior to the onset of hemoglobin degradation, indicating that LAP has an essential role outside of hemoglobin digestion.","method":"Activity-based protein profiling with specific probe, parasite growth inhibition assay, peptidomics","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — selective probe inhibition with defined temporal phenotypic readout; multi-disciplinary approach; specific probe selectivity demonstrated","pmids":["21844374"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2012,"finding":"Using a library of 61 fluorogenic substrates, LAP (PF3D7_1446200) was shown to have a narrow substrate specificity, preferentially cleaving bulky hydrophobic amino acids, and together with PfM1AAP accounts for the majority of aminopeptidase activity in P. falciparum cell lysates.","method":"Fluorogenic substrate library profiling of recombinant enzyme and native parasite lysates","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 1 / Moderate — comprehensive substrate fingerprinting using both recombinant enzyme and native cell lysates; broad library coverage","pmids":["22359643"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2021,"finding":"Cell fractionation and immunolocalization confirmed that LAP (PF3D7_1446200) is exclusively associated with the soluble cytosolic fraction of the parasite with no evidence of presence in the digestive vacuole. Enzyme kinetics showed optimal activity at neutral pH (7.0–8.0), supporting a cytoplasmic function in degrading hemoglobin-derived peptides transported from the digestive vacuole.","method":"Cell fractionation, immunolocalization, enzyme kinetics at varying pH","journal":"Scientific reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — two orthogonal methods (fractionation and immunolocalization) with kinetic characterization; replicates prior localization findings","pmids":["33536500"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"finding":"Using reverse genetics (conditional knockdown) and a compound specifically designed to inhibit LAP (PF3D7_1446200) activity, LAP was shown to be essential for P. falciparum survival, providing free amino acids for growth that are derived from hemoglobin. Loss of LAP activity resulted in parasites exhibiting multiple digestive vacuoles at the trophozoite stage, a phenotype not seen with other hemoglobin-degrading proteases, validating LAP as a non-redundant drug target.","method":"Reverse genetics (conditional knockdown), selective chemical inhibition, phenotypic analysis (microscopy of digestive vacuoles), metabolomics","journal":"eLife","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic and chemical validation with two orthogonal approaches; defined cellular phenotype (multiple DVs); single lab but rigorous multi-method study","pmids":["36097817"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"finding":"LAP (PF3D7_1446200) active site metal ions have a secondary structural role in mediating the formation of active hexamers. LAP exists in a metal-dependent dynamic equilibrium between active hexameric species and smaller inactive species. Mutation of metal-ion-binding residues impaired both catalytic activity and hexamer formation, indicating metal-dependent oligomeric assembly is required for activity.","method":"Site-directed mutagenesis, analytical ultracentrifugation, enzyme kinetics, cryo-EM and X-ray crystallography (of P. vivax ortholog for structural comparison), solution studies","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — mutagenesis combined with structural methods (cryo-EM, crystallography) and solution biochemistry; multiple orthogonal approaches within a single rigorous study","pmids":["33303633"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"finding":"A novel structure of LAP (PF3D7_1446200) revealed that active sites of each trimer are linked by a dynamic loop (L13), and loop movement is coupled with a drastic rearrangement of the binuclear metal center and substrate-binding pocket rendering the protein inactive. This metal-dependent conformational switch is inherent to PfA-M17 and is modulated by signals from the neighboring active site, representing a regulatory mechanism for controlling the rate of proteolysis.","method":"X-ray crystallography (novel inactive conformation), molecular dynamics simulations, biochemical analysis of variants","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure of a novel conformational state combined with MD simulations and biochemical mutagenesis validation; multiple orthogonal methods in one study","pmids":["35691342"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2021,"finding":"Substrate specificity profiling of LAP (PF3D7_1446200) and its orthologs from P. vivax and P. berghei showed that M17 aminopeptidases share a highly conserved preference for hydrophobic residues at the P1 position across Plasmodium species, and that P. falciparum M17 has a slower substrate turnover rate than P. vivax and P. berghei M17, postulated to reflect differences in structural dynamicity.","method":"Fluorogenic substrate library kinetic profiling of recombinant enzymes from multiple Plasmodium species","journal":"The Biochemical journal","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — comprehensive in vitro substrate profiling across species but single lab; mechanistic interpretation (structural dynamicity) is proposed, not directly tested","pmids":["34133730"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""},{"species":"Plasmodium vivax","strain":""},{"species":"Plasmodium berghei","strain":""}]},{"year":2009,"finding":"The P. vivax ortholog of LAP (PvLAP) was expressed recombinantly, showing preferential substrate specificity for leucine-containing substrates, inhibition by EDTA, 1,10-phenanthroline, and bestatin, and was localized by immunofluorescence to the cytoplasm of P. vivax parasites, consistent with a role in hemoglobin catabolism.","method":"Recombinant expression in E. coli, enzyme kinetics, inhibitor studies, immunofluorescence","journal":"Molecular and biochemical parasitology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — enzymatic characterization and direct localization by immunofluorescence; two methods but single lab","pmids":["19931315"],"is_preprint":false,"attribution":[{"species":"Plasmodium vivax","strain":""}]},{"year":2026,"finding":"A mixture of triterpenic phenolic esters (8TTE) was shown to inhibit LAP (PF3D7_1446200, PlasmoDB PF3D7_1446200) enzymatic activity and cause perturbations in hemoglobin metabolism in P. falciparum, with activity onset at the early-ring stage.","method":"Enzymatic inhibition assay, phenotypic analysis, molecular docking, metabolomic profiling","journal":"Malaria journal","confidence":"Low","confidence_rationale":"Tier 3 / Weak — enzymatic assay with complementary docking and metabolomics; single lab, no mechanistic follow-up of binding mode","pmids":["41484625"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"finding":"PPQ-resistant P. falciparum parasites showed increased susceptibility to an inhibitor of LAP (PF3D7_1446200), suggesting that hemoglobin-derived peptide accumulation caused by PPQ resistance mutations in PfCRT increases dependence on LAP activity for peptide metabolism.","method":"Pharmacological inhibition of LAP in isogenic PPQ-resistant/sensitive parasite lines; peptidomics","journal":"PLoS pathogens","confidence":"Low","confidence_rationale":"Tier 3 / Weak — pharmacological inhibition in isogenic lines with peptidomic context; mechanistic link to LAP inferred but not directly probed","pmids":["36306287"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":"Dd2"}]}],"current_model":"LAP (PF3D7_1446200) is a cytosolic, metal-dependent M17 leucyl aminopeptidase that functions as a homo-hexamer to cleave N-terminal hydrophobic amino acids (preferentially leucine) from hemoglobin-derived peptides transported from the digestive vacuole, providing free amino acids essential for parasite growth; hexamer assembly and catalytic activity are regulated by a metal-ion-dependent dynamic equilibrium and a conformational switch involving an inter-active-site loop coupled to rearrangement of the binuclear metal center, and LAP is genetically essential and non-redundant in P. falciparum with loss-of-function causing a distinctive multiple-digestive-vacuole phenotype."},"narrative":{"mechanistic_narrative":"LAP (PF3D7_1446200) is a cytosolic, metal-dependent M17 leucyl aminopeptidase that supplies free amino acids for intra-erythrocytic P. falciparum growth by cleaving N-terminal hydrophobic residues, preferentially leucine, from hemoglobin-derived peptides [PMID:17107951, PMID:36097817]. The enzyme assembles into a functionally active ~320-kDa homo-hexamer whose six active sites face inward around a central catalytic cavity, each gated by flexible loops and bearing a narrow hydrophobic S1 pocket that enforces its restricted specificity for bulky hydrophobic P1 residues [PMID:20133789, PMID:22359643]. Catalysis depends on two active-site metal centers: an exchangeable site 1 (preferring Zn2+) that tunes catalytic efficiency and inhibitor binding, and a tight-binding site 2 whose loss yields an irreversibly inactive apoenzyme [PMID:19408962]. Beyond catalysis, the metal ions play a structural role, driving a dynamic equilibrium between active hexamers and smaller inactive species, and a conformational switch coupling an inter-trimer loop (L13) to rearrangement of the binuclear metal center allows one active site to modulate its neighbor, providing intrinsic regulation of proteolytic rate [PMID:33303633, PMID:35691342]. LAP is genetically essential and non-redundant: conditional knockdown and selective inhibition arrest parasites and produce a distinctive multiple-digestive-vacuole phenotype not seen with other hemoglobin-degrading proteases, and selective probes are lethal even before the onset of hemoglobin digestion, indicating an essential role extending beyond hemoglobin catabolism [PMID:21844374, PMID:36097817]. LAP is the functional antimalarial target of bestatin and other metal-chelating inhibitors [PMID:16286469, PMID:19408962], making it a validated drug target.","teleology":[{"year":2005,"claim":"Establishing that LAP is the cellular target of the antimalarial bestatin was needed to justify it as a drug target rather than one of many parasite aminopeptidases.","evidence":"Transgenic overexpression in P. falciparum with matched enzymatic activity and inhibitor-sensitivity assays","pmids":["16286469"],"confidence":"High","gaps":["Does not resolve whether bestatin resistance from overexpression reflects direct LAP inhibition versus buffering of enzyme pool","Does not establish the physiological substrate in vivo"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2006,"claim":"Reconstituting recombinant LAP defined its core biochemical identity — a metal-dependent, neutral/alkaline-optimal homo-hexamer preferring N-terminal hydrophobic residues — anchoring all later mechanistic work.","evidence":"Recombinant expression in insect cells with enzymatic assays, oligomeric sizing, and substrate profiling; localization by IHC and LAP-GFP fusion","pmids":["17107951","16286469"],"confidence":"High","gaps":["Neutral pH optimum implies cytosolic rather than digestive-vacuole action but does not directly track physiological substrates","Structural basis of hexamer assembly not yet defined"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2009,"claim":"Dissecting the two active-site metal centers explained how metal identity controls catalysis and inhibitor binding, distinguishing a labile from an essential structural metal site.","evidence":"Metal chelation/reconstitution of recombinant enzyme with kinetics and bestatin binding studies","pmids":["19408962"],"confidence":"High","gaps":["Physiological metal occupancy in the parasite cytosol not determined","Link between metal site and oligomeric state not yet made"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2010,"claim":"The hexameric crystal structure explained the enzyme's narrow specificity and inward-facing catalytic architecture, providing a template for inhibitor design.","evidence":"X-ray crystallography of apo and inhibitor-bound hexamer","pmids":["20133789"],"confidence":"High","gaps":["Static structure does not capture conformational dynamics or inactive states","Does not address in-cell assembly regulation"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2011,"claim":"Selective activity-based inhibition showed LAP is lethal early, before hemoglobin digestion begins, implying an essential function beyond hemoglobin catabolism.","evidence":"Activity-based protein profiling with a specific probe, growth inhibition, and peptidomics","pmids":["21844374"],"confidence":"High","gaps":["The non-hemoglobin substrate/pathway underlying early lethality is not identified","Does not exclude off-target probe effects on paralogs"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2012,"claim":"Systematic substrate fingerprinting quantified LAP's narrow hydrophobic preference and its dominant contribution, with PfM1AAP, to parasite aminopeptidase activity.","evidence":"Fluorogenic substrate library profiling of recombinant enzyme and native lysates","pmids":["22359643"],"confidence":"High","gaps":["In vitro peptide substrates do not identify the physiological substrate pool","Functional partitioning between LAP and PfM1AAP in vivo not resolved"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"claim":"Discovering that active-site metals also drive hexamer assembly revealed a structural, not merely catalytic, role for the metal centers and a dynamic oligomeric equilibrium.","evidence":"Site-directed mutagenesis, analytical ultracentrifugation, kinetics, cryo-EM and crystallography (including P. vivax ortholog for comparison)","pmids":["33303633"],"confidence":"High","gaps":["Whether the oligomeric equilibrium is regulated in vivo is untested","Physiological trigger shifting the equilibrium unknown"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2021,"claim":"Fractionation, immunolocalization, and pH profiling consolidated a strictly cytosolic, neutral-pH function processing peptides exported from the digestive vacuole; cross-species profiling showed conserved hydrophobic preference but slower P. falciparum turnover.","evidence":"Cell fractionation and immunolocalization with pH-dependent kinetics; fluorogenic substrate profiling of P. falciparum, P. vivax and P. berghei orthologs","pmids":["33536500","34133730"],"confidence":"High","gaps":["Structural-dynamicity explanation for slower turnover is proposed, not directly tested [#11]","Mechanism of peptide transport from digestive vacuole to cytosol not addressed"],"attribution":[{"species":"Plasmodium falciparum","strain":""},{"species":"Plasmodium vivax","strain":""},{"species":"Plasmodium berghei","strain":""}]},{"year":2022,"claim":"Combined genetic knockdown and selective inhibition established that LAP is essential and non-redundant, with a distinctive multiple-digestive-vacuole phenotype; a novel inactive structure defined a metal-coupled conformational switch regulating proteolysis.","evidence":"Conditional knockdown, selective chemical inhibition, phenotypic microscopy and metabolomics; X-ray crystallography of an inactive conformation with MD simulations and mutagenesis","pmids":["36097817","35691342"],"confidence":"High","gaps":["Mechanistic origin of the multiple-digestive-vacuole phenotype is unexplained","Whether the L13/metal-center switch operates as a regulatory brake in living parasites is untested"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"claim":"Increased LAP dependence in PPQ-resistant parasites tentatively links drug-resistance-driven peptide accumulation to reliance on LAP for peptide clearance.","evidence":"Pharmacological LAP inhibition in isogenic PPQ-resistant/sensitive lines with peptidomics","pmids":["36306287"],"confidence":"Low","gaps":["Mechanistic link to LAP is inferred pharmacologically, not directly probed","Inhibitor selectivity for LAP over other aminopeptidases in this context not confirmed"],"attribution":[{"species":"Plasmodium falciparum","strain":"Dd2"}]},{"year":2026,"claim":"Screening natural-product inhibitors extended the chemical matter targeting LAP, with early-ring-stage activity and hemoglobin-metabolism perturbation.","evidence":"Enzymatic inhibition assay, phenotypic analysis, molecular docking, and metabolomics of a triterpenic phenolic ester mixture","pmids":["41484625"],"confidence":"Low","gaps":["Binding mode inferred from docking only, no structural confirmation","Whether phenotype is driven by LAP inhibition versus other targets not resolved"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":null,"claim":"The essential non-hemoglobin function underlying LAP's early-stage lethality, the identity of its physiological substrates, and how its metal-dependent oligomeric/conformational switching is regulated in living parasites remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No physiological substrate pool defined in vivo","Cellular basis of the multiple-digestive-vacuole phenotype unknown","In-cell regulation of hexamer assembly and the L13 conformational switch untested"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["Homo-hexamer (~320 kDa) with six inward-facing active sites"],"partners":["PFM1AAP (FUNCTIONAL PARTNER ACCOUNTING JOINTLY FOR MOST AMINOPEPTIDASE ACTIVITY IN PARASITE LYSATES; NOT A PHYSICAL COMPLEX)"],"other_free_text":["Functional target of the antimalarial bestatin, validated by gain-of-function resistance on overexpression [#2]","Genetically essential and non-redundant; loss of activity produces a distinctive multiple-digestive-vacuole phenotype at trophozoite stage [#8]","Selective inhibition lethal early in the intra-erythrocytic cycle, before hemoglobin digestion, implying an essential role beyond hemoglobin catabolism [#5]","Metal-dependent conformational switch (loop L13 coupled to binuclear metal-center rearrangement) regulates proteolysis via inter-active-site communication [#10]","Conserved hydrophobic P1 preference across Plasmodium orthologs; P. falciparum enzyme has slower turnover than P. vivax and P. berghei orthologs [#11]","P. vivax ortholog (PvLAP) is cytoplasmic, leucine-preferring, and inhibited by EDTA, 1,10-phenanthroline and bestatin [#12]"]}},"prefetch_data":{},"corpus_meta":[{"pmid":"21844374","id":"PMC_21844374","title":"Bestatin-based chemical biology strategy reveals distinct roles for malaria M1- and M17-family aminopeptidases.","date":"2011","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/21844374","citation_count":109,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["LAP","M17"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"17107951","id":"PMC_17107951","title":"Characterization of the Plasmodium falciparum M17 leucyl aminopeptidase. A protease involved in amino acid regulation with potential for antimalarial drug development.","date":"2006","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17107951","citation_count":101,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["M17 leucyl aminopeptidase","M17"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"19796954","id":"PMC_19796954","title":"Plasmodium falciparum neutral aminopeptidases: new targets for anti-malarials.","date":"2009","source":"Trends in biochemical sciences","url":"https://pubmed.ncbi.nlm.nih.gov/19796954","citation_count":99,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["M17"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"20133789","id":"PMC_20133789","title":"Structure of the Plasmodium falciparum M17 aminopeptidase and significance for the design of drugs targeting the neutral exopeptidases.","date":"2010","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/20133789","citation_count":82,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["M17"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"17960925","id":"PMC_17960925","title":"Identification of phosphinate dipeptide analog inhibitors directed against the Plasmodium falciparum M17 leucine aminopeptidase as lead antimalarial compounds.","date":"2007","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17960925","citation_count":74,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["M17 leucyl aminopeptidase","M17"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"22359643","id":"PMC_22359643","title":"Fingerprinting the substrate specificity of M1 and M17 aminopeptidases of human malaria, Plasmodium falciparum.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/22359643","citation_count":64,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["M17"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"16286469","id":"PMC_16286469","title":"Overexpression of leucyl aminopeptidase in Plasmodium falciparum parasites. 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substrate preference for N-terminally exposed hydrophobic amino acids, particularly leucine.\",\n      \"method\": \"Recombinant expression in insect cells, biochemical characterization (enzymatic assay, size determination)\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstitution of recombinant enzyme with enzymatic assay, substrate profiling, and oligomeric characterization; replicated by multiple subsequent studies\",\n      \"pmids\": [\"17107951\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"LAP (PF3D7_1446200) is localized to the cytosolic compartment of the parasite at all intra-erythrocytic developmental stages, including segregated merozoites, as determined by immunohistochemistry and transfection with a LAP-GFP fusion construct.\",\n      \"method\": \"Immunofluorescence microscopy, GFP-fusion transfection and live imaging\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct localization by two orthogonal methods (IHC and GFP-fusion live imaging), replicated in subsequent studies\",\n      \"pmids\": [\"17107951\", \"16286469\", \"33536500\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Transgenic P. falciparum parasites overexpressing LAP (PF3D7_1446200) showed twice the leucyl aminopeptidase activity in cytosolic extracts and were more resistant to bestatin (EC50 64 µM vs. 25 µM in wild-type), demonstrating that LAP is the functional target of bestatin's antimalarial activity.\",\n      \"method\": \"Parasite transfection (overexpression), enzymatic activity assay on cytosolic extracts, in vitro inhibitor sensitivity assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic overexpression with matched enzymatic and pharmacological readouts; target validation by gain-of-function resistance\",\n      \"pmids\": [\"16286469\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"The active site of LAP (PF3D7_1446200) contains two metal-binding sites: a readily exchangeable site 1 and a tight-binding site 2. Removal of metal from site 1 alone retains activity; removal from both sites yields an inactive apoenzyme that cannot be reactivated. Site 1 shows preference for Zn2+ > Mn2+ > Co2+ > Mg2+, and the identity of the metal at site 1 influences both catalytic efficiency and the binding mode of the inhibitor bestatin.\",\n      \"method\": \"Metal chelation/reconstitution of recombinant enzyme, enzyme kinetics, inhibitor binding studies\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro biochemical reconstitution with metal manipulation and kinetic analysis; single lab but multiple orthogonal methods\",\n      \"pmids\": [\"19408962\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"X-ray crystal structure of LAP (PF3D7_1446200) as a hexamer was solved, revealing that the six active sites are arranged in a disc-like fashion oriented inward to form a central catalytic cavity, with flexible loops at each of the six entrances regulating substrate access. The structure shows a narrow, hydrophobic primary specificity pocket accounting for its restricted substrate specificity, and two metal-binding centers per active site important for substrate and inhibitor binding.\",\n      \"method\": \"X-ray crystallography (apo and inhibitor-bound structures)\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure with inhibitor-bound complexes, multiple structures; replicated in subsequent structural studies\",\n      \"pmids\": [\"20133789\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Specific inhibition of LAP (PF3D7_1446200) using a selective activity-based probe was lethal to P. falciparum parasites early in the intra-erythrocytic life cycle, prior to the onset of hemoglobin degradation, indicating that LAP has an essential role outside of hemoglobin digestion.\",\n      \"method\": \"Activity-based protein profiling with specific probe, parasite growth inhibition assay, peptidomics\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — selective probe inhibition with defined temporal phenotypic readout; multi-disciplinary approach; specific probe selectivity demonstrated\",\n      \"pmids\": [\"21844374\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Using a library of 61 fluorogenic substrates, LAP (PF3D7_1446200) was shown to have a narrow substrate specificity, preferentially cleaving bulky hydrophobic amino acids, and together with PfM1AAP accounts for the majority of aminopeptidase activity in P. falciparum cell lysates.\",\n      \"method\": \"Fluorogenic substrate library profiling of recombinant enzyme and native parasite lysates\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — comprehensive substrate fingerprinting using both recombinant enzyme and native cell lysates; broad library coverage\",\n      \"pmids\": [\"22359643\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Cell fractionation and immunolocalization confirmed that LAP (PF3D7_1446200) is exclusively associated with the soluble cytosolic fraction of the parasite with no evidence of presence in the digestive vacuole. Enzyme kinetics showed optimal activity at neutral pH (7.0–8.0), supporting a cytoplasmic function in degrading hemoglobin-derived peptides transported from the digestive vacuole.\",\n      \"method\": \"Cell fractionation, immunolocalization, enzyme kinetics at varying pH\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — two orthogonal methods (fractionation and immunolocalization) with kinetic characterization; replicates prior localization findings\",\n      \"pmids\": [\"33536500\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Using reverse genetics (conditional knockdown) and a compound specifically designed to inhibit LAP (PF3D7_1446200) activity, LAP was shown to be essential for P. falciparum survival, providing free amino acids for growth that are derived from hemoglobin. Loss of LAP activity resulted in parasites exhibiting multiple digestive vacuoles at the trophozoite stage, a phenotype not seen with other hemoglobin-degrading proteases, validating LAP as a non-redundant drug target.\",\n      \"method\": \"Reverse genetics (conditional knockdown), selective chemical inhibition, phenotypic analysis (microscopy of digestive vacuoles), metabolomics\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic and chemical validation with two orthogonal approaches; defined cellular phenotype (multiple DVs); single lab but rigorous multi-method study\",\n      \"pmids\": [\"36097817\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"LAP (PF3D7_1446200) active site metal ions have a secondary structural role in mediating the formation of active hexamers. LAP exists in a metal-dependent dynamic equilibrium between active hexameric species and smaller inactive species. Mutation of metal-ion-binding residues impaired both catalytic activity and hexamer formation, indicating metal-dependent oligomeric assembly is required for activity.\",\n      \"method\": \"Site-directed mutagenesis, analytical ultracentrifugation, enzyme kinetics, cryo-EM and X-ray crystallography (of P. vivax ortholog for structural comparison), solution studies\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — mutagenesis combined with structural methods (cryo-EM, crystallography) and solution biochemistry; multiple orthogonal approaches within a single rigorous study\",\n      \"pmids\": [\"33303633\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"A novel structure of LAP (PF3D7_1446200) revealed that active sites of each trimer are linked by a dynamic loop (L13), and loop movement is coupled with a drastic rearrangement of the binuclear metal center and substrate-binding pocket rendering the protein inactive. This metal-dependent conformational switch is inherent to PfA-M17 and is modulated by signals from the neighboring active site, representing a regulatory mechanism for controlling the rate of proteolysis.\",\n      \"method\": \"X-ray crystallography (novel inactive conformation), molecular dynamics simulations, biochemical analysis of variants\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure of a novel conformational state combined with MD simulations and biochemical mutagenesis validation; multiple orthogonal methods in one study\",\n      \"pmids\": [\"35691342\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Substrate specificity profiling of LAP (PF3D7_1446200) and its orthologs from P. vivax and P. berghei showed that M17 aminopeptidases share a highly conserved preference for hydrophobic residues at the P1 position across Plasmodium species, and that P. falciparum M17 has a slower substrate turnover rate than P. vivax and P. berghei M17, postulated to reflect differences in structural dynamicity.\",\n      \"method\": \"Fluorogenic substrate library kinetic profiling of recombinant enzymes from multiple Plasmodium species\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — comprehensive in vitro substrate profiling across species but single lab; mechanistic interpretation (structural dynamicity) is proposed, not directly tested\",\n      \"pmids\": [\"34133730\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"},\n        {\"species\": \"Plasmodium vivax\", \"strain\": \"\"},\n        {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"The P. vivax ortholog of LAP (PvLAP) was expressed recombinantly, showing preferential substrate specificity for leucine-containing substrates, inhibition by EDTA, 1,10-phenanthroline, and bestatin, and was localized by immunofluorescence to the cytoplasm of P. vivax parasites, consistent with a role in hemoglobin catabolism.\",\n      \"method\": \"Recombinant expression in E. coli, enzyme kinetics, inhibitor studies, immunofluorescence\",      \"journal\": \"Molecular and biochemical parasitology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — enzymatic characterization and direct localization by immunofluorescence; two methods but single lab\",\n      \"pmids\": [\"19931315\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium vivax\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"A mixture of triterpenic phenolic esters (8TTE) was shown to inhibit LAP (PF3D7_1446200, PlasmoDB PF3D7_1446200) enzymatic activity and cause perturbations in hemoglobin metabolism in P. falciparum, with activity onset at the early-ring stage.\",\n      \"method\": \"Enzymatic inhibition assay, phenotypic analysis, molecular docking, metabolomic profiling\",\n      \"journal\": \"Malaria journal\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — enzymatic assay with complementary docking and metabolomics; single lab, no mechanistic follow-up of binding mode\",\n      \"pmids\": [\"41484625\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"PPQ-resistant P. falciparum parasites showed increased susceptibility to an inhibitor of LAP (PF3D7_1446200), suggesting that hemoglobin-derived peptide accumulation caused by PPQ resistance mutations in PfCRT increases dependence on LAP activity for peptide metabolism.\",\n      \"method\": \"Pharmacological inhibition of LAP in isogenic PPQ-resistant/sensitive parasite lines; peptidomics\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — pharmacological inhibition in isogenic lines with peptidomic context; mechanistic link to LAP inferred but not directly probed\",\n      \"pmids\": [\"36306287\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"Dd2\"}]\n    }\n  ],\n  \"current_model\": \"LAP (PF3D7_1446200) is a cytosolic, metal-dependent M17 leucyl aminopeptidase that functions as a homo-hexamer to cleave N-terminal hydrophobic amino acids (preferentially leucine) from hemoglobin-derived peptides transported from the digestive vacuole, providing free amino acids essential for parasite growth; hexamer assembly and catalytic activity are regulated by a metal-ion-dependent dynamic equilibrium and a conformational switch involving an inter-active-site loop coupled to rearrangement of the binuclear metal center, and LAP is genetically essential and non-redundant in P. falciparum with loss-of-function causing a distinctive multiple-digestive-vacuole phenotype.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"LAP (PF3D7_1446200) is a cytosolic, metal-dependent M17 leucyl aminopeptidase that supplies free amino acids for intra-erythrocytic P. falciparum growth by cleaving N-terminal hydrophobic residues, preferentially leucine, from hemoglobin-derived peptides [#0, #8]. The enzyme assembles into a functionally active ~320-kDa homo-hexamer whose six active sites face inward around a central catalytic cavity, each gated by flexible loops and bearing a narrow hydrophobic S1 pocket that enforces its restricted specificity for bulky hydrophobic P1 residues [#4, #6]. Catalysis depends on two active-site metal centers: an exchangeable site 1 (preferring Zn2+) that tunes catalytic efficiency and inhibitor binding, and a tight-binding site 2 whose loss yields an irreversibly inactive apoenzyme [#3]. Beyond catalysis, the metal ions play a structural role, driving a dynamic equilibrium between active hexamers and smaller inactive species, and a conformational switch coupling an inter-trimer loop (L13) to rearrangement of the binuclear metal center allows one active site to modulate its neighbor, providing intrinsic regulation of proteolytic rate [#9, #10]. LAP is genetically essential and non-redundant: conditional knockdown and selective inhibition arrest parasites and produce a distinctive multiple-digestive-vacuole phenotype not seen with other hemoglobin-degrading proteases, and selective probes are lethal even before the onset of hemoglobin digestion, indicating an essential role extending beyond hemoglobin catabolism [#5, #8]. LAP is the functional antimalarial target of bestatin and other metal-chelating inhibitors [#2, #3], making it a validated drug target.\",\n  \"teleology\": [\n    {\n      \"year\": 2005,\n      \"claim\": \"Establishing that LAP is the cellular target of the antimalarial bestatin was needed to justify it as a drug target rather than one of many parasite aminopeptidases.\",\n      \"evidence\": \"Transgenic overexpression in P. falciparum with matched enzymatic activity and inhibitor-sensitivity assays\",\n      \"pmids\": [\"16286469\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not resolve whether bestatin resistance from overexpression reflects direct LAP inhibition versus buffering of enzyme pool\", \"Does not establish the physiological substrate in vivo\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Reconstituting recombinant LAP defined its core biochemical identity — a metal-dependent, neutral/alkaline-optimal homo-hexamer preferring N-terminal hydrophobic residues — anchoring all later mechanistic work.\",\n      \"evidence\": \"Recombinant expression in insect cells with enzymatic assays, oligomeric sizing, and substrate profiling; localization by IHC and LAP-GFP fusion\",\n      \"pmids\": [\"17107951\", \"16286469\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Neutral pH optimum implies cytosolic rather than digestive-vacuole action but does not directly track physiological substrates\", \"Structural basis of hexamer assembly not yet defined\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Dissecting the two active-site metal centers explained how metal identity controls catalysis and inhibitor binding, distinguishing a labile from an essential structural metal site.\",\n      \"evidence\": \"Metal chelation/reconstitution of recombinant enzyme with kinetics and bestatin binding studies\",\n      \"pmids\": [\"19408962\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological metal occupancy in the parasite cytosol not determined\", \"Link between metal site and oligomeric state not yet made\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"The hexameric crystal structure explained the enzyme's narrow specificity and inward-facing catalytic architecture, providing a template for inhibitor design.\",\n      \"evidence\": \"X-ray crystallography of apo and inhibitor-bound hexamer\",\n      \"pmids\": [\"20133789\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Static structure does not capture conformational dynamics or inactive states\", \"Does not address in-cell assembly regulation\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Selective activity-based inhibition showed LAP is lethal early, before hemoglobin digestion begins, implying an essential function beyond hemoglobin catabolism.\",\n      \"evidence\": \"Activity-based protein profiling with a specific probe, growth inhibition, and peptidomics\",\n      \"pmids\": [\"21844374\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"The non-hemoglobin substrate/pathway underlying early lethality is not identified\", \"Does not exclude off-target probe effects on paralogs\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Systematic substrate fingerprinting quantified LAP's narrow hydrophobic preference and its dominant contribution, with PfM1AAP, to parasite aminopeptidase activity.\",\n      \"evidence\": \"Fluorogenic substrate library profiling of recombinant enzyme and native lysates\",\n      \"pmids\": [\"22359643\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vitro peptide substrates do not identify the physiological substrate pool\", \"Functional partitioning between LAP and PfM1AAP in vivo not resolved\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Discovering that active-site metals also drive hexamer assembly revealed a structural, not merely catalytic, role for the metal centers and a dynamic oligomeric equilibrium.\",\n      \"evidence\": \"Site-directed mutagenesis, analytical ultracentrifugation, kinetics, cryo-EM and crystallography (including P. vivax ortholog for comparison)\",\n      \"pmids\": [\"33303633\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether the oligomeric equilibrium is regulated in vivo is untested\", \"Physiological trigger shifting the equilibrium unknown\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Fractionation, immunolocalization, and pH profiling consolidated a strictly cytosolic, neutral-pH function processing peptides exported from the digestive vacuole; cross-species profiling showed conserved hydrophobic preference but slower P. falciparum turnover.\",\n      \"evidence\": \"Cell fractionation and immunolocalization with pH-dependent kinetics; fluorogenic substrate profiling of P. falciparum, P. vivax and P. berghei orthologs\",\n      \"pmids\": [\"33536500\", \"34133730\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural-dynamicity explanation for slower turnover is proposed, not directly tested [#11]\", \"Mechanism of peptide transport from digestive vacuole to cytosol not addressed\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}, {\"species\": \"Plasmodium vivax\", \"strain\": \"\"}, {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Combined genetic knockdown and selective inhibition established that LAP is essential and non-redundant, with a distinctive multiple-digestive-vacuole phenotype; a novel inactive structure defined a metal-coupled conformational switch regulating proteolysis.\",\n      \"evidence\": \"Conditional knockdown, selective chemical inhibition, phenotypic microscopy and metabolomics; X-ray crystallography of an inactive conformation with MD simulations and mutagenesis\",\n      \"pmids\": [\"36097817\", \"35691342\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanistic origin of the multiple-digestive-vacuole phenotype is unexplained\", \"Whether the L13/metal-center switch operates as a regulatory brake in living parasites is untested\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Increased LAP dependence in PPQ-resistant parasites tentatively links drug-resistance-driven peptide accumulation to reliance on LAP for peptide clearance.\",\n      \"evidence\": \"Pharmacological LAP inhibition in isogenic PPQ-resistant/sensitive lines with peptidomics\",\n      \"pmids\": [\"36306287\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Mechanistic link to LAP is inferred pharmacologically, not directly probed\", \"Inhibitor selectivity for LAP over other aminopeptidases in this context not confirmed\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"Dd2\"}]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Screening natural-product inhibitors extended the chemical matter targeting LAP, with early-ring-stage activity and hemoglobin-metabolism perturbation.\",\n      \"evidence\": \"Enzymatic inhibition assay, phenotypic analysis, molecular docking, and metabolomics of a triterpenic phenolic ester mixture\",\n      \"pmids\": [\"41484625\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Binding mode inferred from docking only, no structural confirmation\", \"Whether phenotype is driven by LAP inhibition versus other targets not resolved\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The essential non-hemoglobin function underlying LAP's early-stage lethality, the identity of its physiological substrates, and how its metal-dependent oligomeric/conformational switching is regulated in living parasites remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No physiological substrate pool defined in vivo\", \"Cellular basis of the multiple-digestive-vacuole phenotype unknown\", \"In-cell regulation of hexamer assembly and the L13 conformational switch untested\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0004177\", \"supporting_discovery_ids\": [0, 6, 12]},\n      {\"term_id\": \"GO:0070006\", \"supporting_discovery_ids\": [0, 4, 6]},\n      {\"term_id\": \"GO:0008270\", \"supporting_discovery_ids\": [3, 9]},\n      {\"term_id\": \"GO:0046872\", \"supporting_discovery_ids\": [3, 9, 10]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1, 7]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0043171\", \"supporting_discovery_ids\": [0, 8]},\n      {\"term_id\": \"GO:0006508\", \"supporting_discovery_ids\": [0, 6, 8]}\n    ],\n    \"complexes\": [\n      \"Homo-hexamer (~320 kDa) with six inward-facing active sites\"\n    ],\n    \"partners\": [\n      \"PfM1AAP (functional partner accounting jointly for most aminopeptidase activity in parasite lysates; not a physical complex)\"\n    ],\n    \"other_free_text\": [\n      \"Functional target of the antimalarial bestatin, validated by gain-of-function resistance on overexpression [#2]\",\n      \"Genetically essential and non-redundant; loss of activity produces a distinctive multiple-digestive-vacuole phenotype at trophozoite stage [#8]\",\n      \"Selective inhibition lethal early in the intra-erythrocytic cycle, before hemoglobin digestion, implying an essential role beyond hemoglobin catabolism [#5]\",\n      \"Metal-dependent conformational switch (loop L13 coupled to binuclear metal-center rearrangement) regulates proteolysis via inter-active-site communication [#10]\",\n      \"Conserved hydrophobic P1 preference across Plasmodium orthologs; P. falciparum enzyme has slower turnover than P. vivax and P. berghei orthologs [#11]\",\n      \"P. vivax ortholog (PvLAP) is cytoplasmic, leucine-preferring, and inhibited by EDTA, 1,10-phenanthroline and bestatin [#12]\"\n    ]\n  }\n}","audit_flag":null,"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_1446200","name":null,"product":"M17 leucyl aminopeptidase","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PbANKA","gene_id":"PBANKA_1309900","name":null,"product":"M17 leucyl aminopeptidase, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PkH","gene_id":"PKNH_1236000","name":null,"product":"M17 leucyl aminopeptidase, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"LAP","evaluation":null}