{"gene":"PF3D7_1201800","run_date":"2026-09-08T16:26:55","timeline":{"discoveries":[{"year":2023,"finding":"Recombinant P. falciparum COX19 (PF3D7_1201800), expressed as a fusion with maltose binding protein, binds copper as measured by four independent in vitro/in vivo assays: bicinchoninic acid release assay, bacterial host growth inhibition assay, ascorbate oxidation inhibition, and differential scanning fluorimetry. The protein contains two Cx9C Cox19 copper-binding motifs and is predicted to associate with PfCox11 in inserting copper into the CuB site of Plasmodium cytochrome c oxidase.","method":"Recombinant protein expression, affinity purification, bicinchoninic acid copper-release assay, bacterial growth inhibition assay, ascorbate oxidation inhibition assay, differential scanning fluorimetry; native protein detected by antibodies raised against the recombinant protein","journal":"Experimental parasitology","confidence":"Medium","confidence_rationale":"Tier 1–2 / Weak — four orthogonal in vitro copper-binding methods in a single lab study; functional in vivo validation limited to bacterial surrogate assay; predicted but not experimentally confirmed interaction with PfCox11","pmids":["37348640"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"finding":"Native P. falciparum COX19 protein (PF3D7_1201800, ~26.1 kDa) is expressed in blood-stage parasites; antibodies against PfCox11 detected a ~58 kDa band in parasite lysate that may represent a heterodimer of PfCox11 and PfCox19, consistent with the known yeast Cox11–Cox19 interaction, though this was not directly confirmed.","method":"Western blot of blood-stage parasite lysate using anti-PfCox11 antibodies; size inference for heterodimer","journal":"Malaria journal","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single indirect western blot observation; heterodimer identity inferred by size and not confirmed by co-immunoprecipitation or pulldown","pmids":["35672733"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2025,"finding":"P. falciparum COX19 (PF3D7_1201800) is identified as one of the lineage-specific subunits of P. falciparum Complex IV (cytochrome c oxidase), which is notably larger (~570 kDa, 22 subunits) than the yeast complex (~200 kDa, 12–13 subunits), placing COX19 as a component of the assembled complex.","method":"Biochemical characterization of Complex IV composition (review/proteomics-based identification cited from prior studies)","journal":"International journal of molecular sciences","confidence":"Low","confidence_rationale":"Tier 3 / Weak — membership in Complex IV reported in a review citing prior proteomic data; no direct reconstitution or structural validation described for this specific subunit in this paper","pmids":["41009722"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"current_model":"P. falciparum COX19 (PF3D7_1201800) is a 26 kDa mitochondrial protein with two Cx9C copper-binding motifs that binds copper in vitro, is expressed in blood-stage parasites, and is proposed to function in copper insertion into the CuB site of cytochrome c oxidase by associating with PfCox11; it is also identified as a lineage-specific subunit of the P. falciparum Complex IV assembly."},"narrative":{"mechanistic_narrative":"COX19 (PF3D7_1201800) is a ~26 kDa P. falciparum protein implicated in copper handling during cytochrome c oxidase (Complex IV) biogenesis [PMID:37348640]. Recombinant COX19 binds copper, as established by four orthogonal in vitro and surrogate in vivo assays (bicinchoninic acid copper-release, bacterial growth inhibition, ascorbate oxidation inhibition, and differential scanning fluorimetry), and it carries two Cx9C copper-binding motifs; on this basis it is positioned to insert copper into the CuB site of Plasmodium cytochrome c oxidase in association with PfCox11 [PMID:37348640]. The native protein is expressed in blood-stage parasites [PMID:35672733]. Beyond its copper-binding activity and predicted PfCox11 partnership, the mechanism of COX19 is not directly characterized in the available corpus: the association with PfCox11 remains inferential (based on a size-inferred ~58 kDa band, not a direct interaction assay), and its assignment as a lineage-specific subunit of the enlarged P. falciparum Complex IV derives from cited proteomic data rather than direct validation of this subunit [PMID:35672733, PMID:41009722].","teleology":[{"year":2022,"claim":"Establishing that COX19 protein is actually made by the parasite was the first step in moving it from a predicted ORF to a candidate Complex IV factor, and a co-migrating band raised the possibility of a PfCox11 partnership.","evidence":"Western blot of blood-stage parasite lysate, with size inference of a putative PfCox11-PfCox19 heterodimer","pmids":["35672733"],"confidence":"Low","gaps":["Heterodimer identity inferred from a ~58 kDa band only; not confirmed by co-immunoprecipitation or pulldown","No direct evidence of COX19-PfCox11 physical interaction","No stage specificity or subcellular localization established"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2023,"claim":"The central question of what COX19 does biochemically was addressed by showing it is a copper-binding protein with Cx9C motifs, supporting a role in delivering copper to the CuB site of cytochrome c oxidase.","evidence":"Recombinant MBP-fusion COX19 assayed by four orthogonal copper-binding methods; native protein detected with antibodies against the recombinant protein","pmids":["37348640"],"confidence":"Medium","gaps":["Functional in vivo validation limited to a bacterial surrogate assay, not P. falciparum","Association with PfCox11 predicted but not experimentally confirmed","Copper delivery to the CuB site not demonstrated directly"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2025,"claim":"Placing COX19 within the assembled complex, it was catalogued as a lineage-specific subunit of the atypically large P. falciparum Complex IV, framing it as part of a parasite-divergent oxidase.","evidence":"Biochemical/proteomics-based composition analysis of P. falciparum Complex IV (review citing prior data)","pmids":["41009722"],"confidence":"Low","gaps":["Membership derives from cited proteomic data; no direct reconstitution or structural validation of this subunit in this work","Distinction between a transient assembly factor role and a stable structural subunit not resolved","Stoichiometry and position within the 22-subunit complex unknown"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":null,"claim":"Whether COX19 physically interacts with PfCox11 and functionally delivers copper to cytochrome c oxidase in living parasites remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No direct interaction assay (co-IP, pulldown) between COX19 and PfCox11","No genetic knockout/knockdown phenotype for COX19 in P. falciparum","No structural placement within the assembled Complex IV"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["P. falciparum Complex IV (cytochrome c oxidase) [#2]"],"partners":["PFCOX11 (PREDICTED/INFERRED, NOT DIRECTLY CONFIRMED) [#0, #1]"],"other_free_text":["Contains two Cx9C Cox19 copper-binding motifs [#0]","~26 kDa protein expressed in blood-stage parasites [#1]","Proposed to insert copper into the CuB site of Plasmodium cytochrome c oxidase [#0]"]}},"prefetch_data":{},"corpus_meta":[{"pmid":"37348640","id":"PMC_37348640","title":"Expression and copper binding studies of a Plasmodium falciparum protein with Cox19 copper binding motifs.","date":"2023","source":"Experimental parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/37348640","citation_count":2,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["COX19","PfCOX19"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"41009722","id":"","title":"Targeting Mitochondrial Function in Plasmodium falciparum: Insight into Antimalarial Drugs and the Emerging Role of Saccharomyces cerevisiae as a Model System.","date":"2025","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/41009722","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["COX19"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"35672733","id":"","title":"Expression and copper binding characteristics of Plasmodium falciparum cytochrome c oxidase assembly factor 11, Cox11.","date":"2022","source":"Malaria journal","url":"https://pubmed.ncbi.nlm.nih.gov/35672733","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["COX19"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"29241459","id":"","title":"To Mia or not to Mia: stepwise evolution of the mitochondrial intermembrane space disulfide relay.","date":"2017","source":"BMC biology","url":"https://pubmed.ncbi.nlm.nih.gov/29241459","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["COX19"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"29117860","id":"","title":"Erv1 of Arabidopsis thaliana can directly oxidize mitochondrial intermembrane space proteins in the absence of redox-active Mia40.","date":"2017","source":"BMC biology","url":"https://pubmed.ncbi.nlm.nih.gov/29117860","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["COX19"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7085,"output_tokens":1059,"usd":0.01857,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":5818,"output_tokens":1906,"usd":0.03837,"stage2_stop_reason":"end_turn"},"total_usd":0.05694,"stage1_batch_id":"msgbatch_01NE1MTa8x1hW7Lo4tAaNzY1","stage2_batch_id":"msgbatch_0141vaQdeFvbo2q39AinvXM9","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2023,\n      \"finding\": \"Recombinant P. falciparum COX19 (PF3D7_1201800), expressed as a fusion with maltose binding protein, binds copper as measured by four independent in vitro/in vivo assays: bicinchoninic acid release assay, bacterial host growth inhibition assay, ascorbate oxidation inhibition, and differential scanning fluorimetry. The protein contains two Cx9C Cox19 copper-binding motifs and is predicted to associate with PfCox11 in inserting copper into the CuB site of Plasmodium cytochrome c oxidase.\",\n      \"method\": \"Recombinant protein expression, affinity purification, bicinchoninic acid copper-release assay, bacterial growth inhibition assay, ascorbate oxidation inhibition assay, differential scanning fluorimetry; native protein detected by antibodies raised against the recombinant protein\",\n      \"journal\": \"Experimental parasitology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1–2 / Weak — four orthogonal in vitro copper-binding methods in a single lab study; functional in vivo validation limited to bacterial surrogate assay; predicted but not experimentally confirmed interaction with PfCox11\",\n      \"pmids\": [\"37348640\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Native P. falciparum COX19 protein (PF3D7_1201800, ~26.1 kDa) is expressed in blood-stage parasites; antibodies against PfCox11 detected a ~58 kDa band in parasite lysate that may represent a heterodimer of PfCox11 and PfCox19, consistent with the known yeast Cox11–Cox19 interaction, though this was not directly confirmed.\",\n      \"method\": \"Western blot of blood-stage parasite lysate using anti-PfCox11 antibodies; size inference for heterodimer\",\n      \"journal\": \"Malaria journal\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single indirect western blot observation; heterodimer identity inferred by size and not confirmed by co-immunoprecipitation or pulldown\",\n      \"pmids\": [\"35672733\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"P. falciparum COX19 (PF3D7_1201800) is identified as one of the lineage-specific subunits of P. falciparum Complex IV (cytochrome c oxidase), which is notably larger (~570 kDa, 22 subunits) than the yeast complex (~200 kDa, 12–13 subunits), placing COX19 as a component of the assembled complex.\",\n      \"method\": \"Biochemical characterization of Complex IV composition (review/proteomics-based identification cited from prior studies)\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — membership in Complex IV reported in a review citing prior proteomic data; no direct reconstitution or structural validation described for this specific subunit in this paper\",\n      \"pmids\": [\"41009722\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"current_model\": \"P. falciparum COX19 (PF3D7_1201800) is a 26 kDa mitochondrial protein with two Cx9C copper-binding motifs that binds copper in vitro, is expressed in blood-stage parasites, and is proposed to function in copper insertion into the CuB site of cytochrome c oxidase by associating with PfCox11; it is also identified as a lineage-specific subunit of the P. falciparum Complex IV assembly.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"COX19 (PF3D7_1201800) is a ~26 kDa P. falciparum protein implicated in copper handling during cytochrome c oxidase (Complex IV) biogenesis [#0]. Recombinant COX19 binds copper, as established by four orthogonal in vitro and surrogate in vivo assays (bicinchoninic acid copper-release, bacterial growth inhibition, ascorbate oxidation inhibition, and differential scanning fluorimetry), and it carries two Cx9C copper-binding motifs; on this basis it is positioned to insert copper into the CuB site of Plasmodium cytochrome c oxidase in association with PfCox11 [#0]. The native protein is expressed in blood-stage parasites [#1]. Beyond its copper-binding activity and predicted PfCox11 partnership, the mechanism of COX19 is not directly characterized in the available corpus: the association with PfCox11 remains inferential (based on a size-inferred ~58 kDa band, not a direct interaction assay), and its assignment as a lineage-specific subunit of the enlarged P. falciparum Complex IV derives from cited proteomic data rather than direct validation of this subunit [#1, #2].\",\n  \"teleology\": [\n    {\n      \"year\": 2022,\n      \"claim\": \"Establishing that COX19 protein is actually made by the parasite was the first step in moving it from a predicted ORF to a candidate Complex IV factor, and a co-migrating band raised the possibility of a PfCox11 partnership.\",\n      \"evidence\": \"Western blot of blood-stage parasite lysate, with size inference of a putative PfCox11-PfCox19 heterodimer\",\n      \"pmids\": [\"35672733\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"Heterodimer identity inferred from a ~58 kDa band only; not confirmed by co-immunoprecipitation or pulldown\",\n        \"No direct evidence of COX19-PfCox11 physical interaction\",\n        \"No stage specificity or subcellular localization established\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"The central question of what COX19 does biochemically was addressed by showing it is a copper-binding protein with Cx9C motifs, supporting a role in delivering copper to the CuB site of cytochrome c oxidase.\",\n      \"evidence\": \"Recombinant MBP-fusion COX19 assayed by four orthogonal copper-binding methods; native protein detected with antibodies against the recombinant protein\",\n      \"pmids\": [\"37348640\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Functional in vivo validation limited to a bacterial surrogate assay, not P. falciparum\",\n        \"Association with PfCox11 predicted but not experimentally confirmed\",\n        \"Copper delivery to the CuB site not demonstrated directly\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Placing COX19 within the assembled complex, it was catalogued as a lineage-specific subunit of the atypically large P. falciparum Complex IV, framing it as part of a parasite-divergent oxidase.\",\n      \"evidence\": \"Biochemical/proteomics-based composition analysis of P. falciparum Complex IV (review citing prior data)\",\n      \"pmids\": [\"41009722\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"Membership derives from cited proteomic data; no direct reconstitution or structural validation of this subunit in this work\",\n        \"Distinction between a transient assembly factor role and a stable structural subunit not resolved\",\n        \"Stoichiometry and position within the 22-subunit complex unknown\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Whether COX19 physically interacts with PfCox11 and functionally delivers copper to cytochrome c oxidase in living parasites remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No direct interaction assay (co-IP, pulldown) between COX19 and PfCox11\",\n        \"No genetic knockout/knockdown phenotype for COX19 in P. falciparum\",\n        \"No structural placement within the assembled Complex IV\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005507\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [],\n    \"pathway\": [\n      {\"term_id\": \"GO:0033617\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"complexes\": [\n      \"P. falciparum Complex IV (cytochrome c oxidase) [#2]\"\n    ],\n    \"partners\": [\n      \"PfCox11 (predicted/inferred, not directly confirmed) [#0, #1]\"\n    ],\n    \"other_free_text\": [\n      \"Contains two Cx9C Cox19 copper-binding motifs [#0]\",\n      \"~26 kDa protein expressed in blood-stage parasites [#1]\",\n      \"Proposed to insert copper into the CuB site of Plasmodium cytochrome c oxidase [#0]\"\n    ]\n  }\n}","audit_flag":null,"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_1201800","name":null,"product":"cytochrome c oxidase assembly protein COX19, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PbANKA","gene_id":"PBANKA_0600800","name":null,"product":"cytochrome c oxidase assembly protein COX19, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PkH","gene_id":"PKNH_1301700","name":null,"product":"cytochrome c oxidase assembly protein COX19, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"COX19","evaluation":null}