{"gene":"PKNH_0516100","run_date":"2026-09-08T15:24:05","timeline":{"discoveries":[{"year":2015,"finding":"PKNH_0516100 (PkTRAg40.1) binds to human erythrocytes, as demonstrated by cell-ELISA and in vitro rosetting assay using recombinant protein expressed in E. coli and CHO-K1 cells. PkTRAg40.1 cross-competes with PkTRAg38.3 and with P. vivax tryptophan-rich antigens (PvTRAgs) for the same human erythrocyte receptor(s), indicating shared receptor usage. Additionally, PkTRAg40.1 inhibited P. falciparum parasite growth in in vitro culture, further supporting its role in erythrocyte receptor–ligand interaction.","method":"Cell-ELISA with recombinant protein expressed in E. coli and CHO-K1 mammalian cells; in vitro rosetting assay; cross-competition binding assay; in vitro P. falciparum growth inhibition assay","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — two orthogonal binding assays (cell-ELISA and rosetting) plus cross-competition and growth inhibition, but single lab and no structural or mutagenesis validation","pmids":["26393350"],"is_preprint":false,"attribution":[{"species":"Plasmodium knowlesi","strain":""}]}],"current_model":"PKNH_0516100 (TRAG40.1/PkTRAg40.1) is a P. knowlesi tryptophan-rich antigen that binds human erythrocytes via receptor(s) shared with other P. knowlesi TRAgs and P. vivax TRAgs, and its presence inhibits P. falciparum growth in vitro, implicating it in erythrocyte invasion or attachment during zoonotic human infection."},"narrative":{"mechanistic_narrative":"PKNH_0516100 (TRAG40.1) is a Plasmodium knowlesi tryptophan-rich antigen implicated in erythrocyte attachment during infection [PMID:26393350]. Recombinant PKNH_0516100 expressed in E. coli and CHO-K1 cells binds human erythrocytes in cell-ELISA and in vitro rosetting assays, and cross-competes with the P. knowlesi antigen PkTRAg38.3 and with P. vivax tryptophan-rich antigens for the same host erythrocyte receptor(s), indicating shared receptor usage among these tryptophan-rich antigens [PMID:26393350]. Addition of the protein inhibits P. falciparum growth in vitro, consistent with a role in erythrocyte receptor–ligand interaction [PMID:26393350]. Beyond this erythrocyte-binding characterization [PMID:26393350], no structural, mutagenesis, or in vivo mechanistic detail for PKNH_0516100 has been characterized in the available corpus, and the specific host receptor engaged remains unidentified.","teleology":[{"year":2015,"claim":"Establishing whether PKNH_0516100 engages host cells, this work showed the recombinant antigen binds human erythrocytes and shares receptor usage with other tryptophan-rich antigens, positioning it as a candidate ligand in erythrocyte attachment/invasion.","evidence":"cell-ELISA and in vitro rosetting with recombinant protein from E. coli and CHO-K1, cross-competition binding, and P. falciparum growth-inhibition assay","pmids":["26393350"],"confidence":"Medium","gaps":["The specific human erythrocyte receptor bound is not identified","No structural or mutagenesis data defining the binding interface","Role in actual P. knowlesi invasion/growth demonstrated only indirectly via P. falciparum growth inhibition, not by direct genetic manipulation of the gene"],"attribution":[{"species":"Plasmodium knowlesi","strain":""}]},{"year":null,"claim":"The molecular identity of the shared erythrocyte receptor and the physiological function of PKNH_0516100 during native P. knowlesi invasion remain unresolved.","evidence":"no further discoveries in the available corpus","pmids":[],"confidence":"Medium","gaps":["Host receptor unidentified","No loss-of-function/genetic evidence in P. knowlesi","No structural characterization of the binding domain"],"attribution":[{"species":"Plasmodium knowlesi","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["HUMAN ERYTHROCYTE RECEPTOR(S) (SHARED, UNIDENTIFIED) [#0]","CROSS-COMPETES WITH PKTRAG38.3 FOR THE SAME RECEPTOR [#0]","CROSS-COMPETES WITH P. VIVAX TRYPTOPHAN-RICH ANTIGENS (PVTRAGS) FOR THE SAME RECEPTOR [#0]"],"other_free_text":["Binds human erythrocytes in cell-ELISA and rosetting assays using recombinant protein [#0]","Inhibits P. falciparum growth in vitro, consistent with a role in erythrocyte receptor–ligand interaction [#0]","Tryptophan-rich antigen of P. knowlesi [#0]"]}},"prefetch_data":{},"corpus_meta":[{"pmid":"11704272","id":"PMC_11704272","title":"Properties of the Plasmodium falciparum homologue of a protective vaccine candidate of Plasmodium yoelii.","date":"2001","source":"Molecular and biochemical parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/11704272","citation_count":22,"is_preprint":false,"source_species":["Pk"],"role":"primary","match_terms":["tryptophan-rich protein"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"25960542","id":"PMC_25960542","title":"A Sporozoite- and Liver Stage-expressed Tryptophan-rich Protein Plays an Auxiliary Role in Plasmodium Liver Stage Development and Is a Potential Vaccine Candidate.","date":"2015","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/25960542","citation_count":19,"is_preprint":false,"source_species":["Pk"],"role":"primary","match_terms":["tryptophan-rich protein"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"18603013","id":"PMC_18603013","title":"Immunological responses to a 39.8kDa Plasmodium vivax tryptophan-rich antigen (PvTRAg39.8) among humans.","date":"2008","source":"Microbes and infection","url":"https://pubmed.ncbi.nlm.nih.gov/18603013","citation_count":16,"is_preprint":false,"source_species":["Pk"],"role":"primary","match_terms":["tryptophan-rich protein"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"21464256","id":"PMC_21464256","title":"Artesunate tolerance in transgenic Plasmodium falciparum parasites overexpressing a tryptophan-rich protein.","date":"2011","source":"Antimicrobial agents and chemotherapy","url":"https://pubmed.ncbi.nlm.nih.gov/21464256","citation_count":15,"is_preprint":false,"source_species":["Pk"],"role":"primary","match_terms":["tryptophan-rich protein"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"21283717","id":"PMC_21283717","title":"Plasmodium vivax tryptophan-rich antigen PvTRAg33.5 contains alpha helical structure and multidomain architecture.","date":"2011","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/21283717","citation_count":10,"is_preprint":false,"source_species":["Pk"],"role":"primary","match_terms":["tryptophan-rich protein"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"26393350","id":"PMC_26393350","title":"Recognition of Human Erythrocyte Receptors by the Tryptophan-Rich Antigens of Monkey Malaria Parasite Plasmodium knowlesi.","date":"2015","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/26393350","citation_count":9,"is_preprint":false,"source_species":["Pk"],"role":"primary","match_terms":["curated_ref"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"36126089","id":"PMC_36126089","title":"A member of the tryptophan-rich protein family is required for efficient sequestration of Plasmodium berghei schizonts.","date":"2022","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/36126089","citation_count":8,"is_preprint":false,"source_species":["Pk"],"role":"primary","match_terms":["tryptophan-rich protein"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"35744665","id":"PMC_35744665","title":"Genetic Diversity and Phylogenetic Relatedness of Plasmodium ovale curtisi and Plasmodium ovale wallikeri in sub-Saharan Africa.","date":"2022","source":"Microorganisms","url":"https://pubmed.ncbi.nlm.nih.gov/35744665","citation_count":1,"is_preprint":false,"source_species":["Pk"],"role":"primary","match_terms":["tryptophan-rich protein"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"41810678","id":"PMC_41810678","title":"Transcriptomics of Plasmodium vivax rosetting.","date":"2026","source":"Memorias do Instituto Oswaldo Cruz","url":"https://pubmed.ncbi.nlm.nih.gov/41810678","citation_count":0,"is_preprint":false,"source_species":["Pk"],"role":"primary","match_terms":["tryptophan-rich protein"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"41983137","id":"PMC_41983137","title":"Poly(I:C) and R848 adjuvants elicit sizeable humoral immunity to liver stage malaria antigens.","date":"2026","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/41983137","citation_count":0,"is_preprint":false,"source_species":["Pk"],"role":"primary","match_terms":["tryptophan-rich protein"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":8079,"output_tokens":1045,"usd":0.019956,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":5040,"output_tokens":1269,"usd":0.028463,"stage2_stop_reason":"end_turn"},"total_usd":0.048419,"stage1_batch_id":"msgbatch_01S4WrhSkksYHeZXxqf3za3o","stage2_batch_id":"msgbatch_019VBBeuW6G52X8gZfsFDfb5","note":"batch pricing = 50% of standard"},"stage1_raw":"Looking at the corpus, I need to identify papers that describe mechanistic findings specifically about PKNH_0516100 (TRAG40.1), which is a P. knowlesi tryptophan-rich protein.\n\nLet me classify each paper:\n\n1. **PMID:11704272** - About P. falciparum homologue (Pf TRP), not PKNH_0516100 specifically. Some structural characterization but of a different species' protein.\n\n2. **PMID:25960542** - About SLTRiP (sporozoite/liver stage TRiP) in P. berghei/rodent malaria. Not PKNH_0516100.\n\n3. **PMID:18603003** - About PvTRAg39.8 in P. vivax. Not PKNH_0516100.\n\n4. **PMID:21464256** - About PArt (Pf10_0026) in P. falciparum. Not PKNH_0516100.\n\n5. **PMID:21283717** - About PvTRAg33.5 in P. vivax. Not PKNH_0516100.\n\n6. **PMID:26393350** - About P. knowlesi TRAgs including **PkTRAg40.1**, which corresponds to PKNH_0516100/TRAG40.1. This paper directly studies this gene. Contains mechanistic findings about erythrocyte binding.\n\n7. **PMID:36126089** - About IPIS2/IPIS3 in P. berghei. Not PKNH_0516100.\n\n8. **PMID:35744665** - Genetic diversity of P. ovale. Not PKNH_0516100.\n\n9. **PMID:41810678** - About P. vivax rosetting; mentions TRAG16, not TRAG40.1.\n\n10. **PMID:41983137** - About PbSLTRiP and PfCSP. Not PKNH_0516100.\n\nOnly PMID:26393350 directly studies PkTRAg40.1 (PKNH_0516100/TRAG40.1).\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2015,\n      \"finding\": \"PKNH_0516100 (PkTRAg40.1) binds to human erythrocytes, as demonstrated by cell-ELISA and in vitro rosetting assay using recombinant protein expressed in E. coli and CHO-K1 cells. PkTRAg40.1 cross-competes with PkTRAg38.3 and with P. vivax tryptophan-rich antigens (PvTRAgs) for the same human erythrocyte receptor(s), indicating shared receptor usage. Additionally, PkTRAg40.1 inhibited P. falciparum parasite growth in in vitro culture, further supporting its role in erythrocyte receptor–ligand interaction.\",\n      \"method\": \"Cell-ELISA with recombinant protein expressed in E. coli and CHO-K1 mammalian cells; in vitro rosetting assay; cross-competition binding assay; in vitro P. falciparum growth inhibition assay\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — two orthogonal binding assays (cell-ELISA and rosetting) plus cross-competition and growth inhibition, but single lab and no structural or mutagenesis validation\",\n      \"pmids\": [\"26393350\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium knowlesi\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"current_model\": \"PKNH_0516100 (TRAG40.1/PkTRAg40.1) is a P. knowlesi tryptophan-rich antigen that binds human erythrocytes via receptor(s) shared with other P. knowlesi TRAgs and P. vivax TRAgs, and its presence inhibits P. falciparum growth in vitro, implicating it in erythrocyte invasion or attachment during zoonotic human infection.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PKNH_0516100 (TRAG40.1) is a Plasmodium knowlesi tryptophan-rich antigen implicated in erythrocyte attachment during infection [#0]. Recombinant PKNH_0516100 expressed in E. coli and CHO-K1 cells binds human erythrocytes in cell-ELISA and in vitro rosetting assays, and cross-competes with the P. knowlesi antigen PkTRAg38.3 and with P. vivax tryptophan-rich antigens for the same host erythrocyte receptor(s), indicating shared receptor usage among these tryptophan-rich antigens [#0]. Addition of the protein inhibits P. falciparum growth in vitro, consistent with a role in erythrocyte receptor–ligand interaction [#0]. Beyond this erythrocyte-binding characterization [#0], no structural, mutagenesis, or in vivo mechanistic detail for PKNH_0516100 has been characterized in the available corpus, and the specific host receptor engaged remains unidentified.\",\n  \"teleology\": [\n    {\n      \"year\": 2015,\n      \"claim\": \"Establishing whether PKNH_0516100 engages host cells, this work showed the recombinant antigen binds human erythrocytes and shares receptor usage with other tryptophan-rich antigens, positioning it as a candidate ligand in erythrocyte attachment/invasion.\",\n      \"evidence\": \"cell-ELISA and in vitro rosetting with recombinant protein from E. coli and CHO-K1, cross-competition binding, and P. falciparum growth-inhibition assay\",\n      \"pmids\": [\"26393350\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"The specific human erythrocyte receptor bound is not identified\",\n        \"No structural or mutagenesis data defining the binding interface\",\n        \"Role in actual P. knowlesi invasion/growth demonstrated only indirectly via P. falciparum growth inhibition, not by direct genetic manipulation of the gene\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium knowlesi\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular identity of the shared erythrocyte receptor and the physiological function of PKNH_0516100 during native P. knowlesi invasion remain unresolved.\",\n      \"evidence\": \"no further discoveries in the available corpus\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Host receptor unidentified\",\n        \"No loss-of-function/genetic evidence in P. knowlesi\",\n        \"No structural characterization of the binding domain\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium knowlesi\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [],\n    \"pathway\": [],\n    \"complexes\": [],\n    \"partners\": [\n      \"human erythrocyte receptor(s) (shared, unidentified) [#0]\",\n      \"cross-competes with PkTRAg38.3 for the same receptor [#0]\",\n      \"cross-competes with P. vivax tryptophan-rich antigens (PvTRAgs) for the same receptor [#0]\"\n    ],\n    \"other_free_text\": [\n      \"Binds human erythrocytes in cell-ELISA and rosetting assays using recombinant protein [#0]\",\n      \"Inhibits P. falciparum growth in vitro, consistent with a role in erythrocyte receptor–ligand interaction [#0]\",\n      \"Tryptophan-rich antigen of P. knowlesi [#0]\"\n    ]\n  }\n}","audit_flag":null,"strains":[{"strain":"PkH","gene_id":"PKNH_0516100","name":null,"product":"tryptophan-rich protein","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"","evaluation":null}