{"gene":"PF3D7_1414600","run_date":"2026-09-08T14:19:07","timeline":{"discoveries":[{"year":2001,"finding":"PF3D7_1414600 (Pgt1) encodes a separate RNA guanylyltransferase enzyme in P. falciparum, functioning as the mRNA-capping guanylyltransferase subunit alpha, distinct from the RNA triphosphatase (Prt1) component. The two activities are carried out by separate proteins (not fused), resembling the fungal/yeast capping apparatus rather than the metazoan one.","method":"Biochemical analysis and sequence/functional characterization of the P. falciparum mRNA capping apparatus, identifying Pgt1 as the guanylyltransferase and Prt1 as the triphosphatase as separate enzymes","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — functional characterization from a single lab identifying enzymatic activity and establishing the two-subunit architecture, but abstract does not detail in vitro reconstitution or mutagenesis for Pgt1 specifically","pmids":["11248030"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"current_model":"PF3D7_1414600 (Pgt1) is the RNA guanylyltransferase subunit of the P. falciparum mRNA-capping apparatus, functioning as a separate enzyme from the RNA triphosphatase (Prt1) in a yeast-like two-component capping system rather than the fused metazoan-type enzyme."},"narrative":{"mechanistic_narrative":"PF3D7_1414600 (Pgt1) is the RNA guanylyltransferase of the Plasmodium falciparum mRNA-capping apparatus, functioning as the guanylyltransferase subunit alpha that is physically distinct from the RNA triphosphatase component (Prt1) [PMID:11248030]. This two-component organization, in which the triphosphatase and guanylyltransferase activities are carried out by separate proteins rather than a single fused polypeptide, resembles the fungal/yeast capping system rather than the metazoan-type enzyme [PMID:11248030]. Beyond this identification of Pgt1 as the separate guanylyltransferase subunit, no further mechanistic detail — in vitro reconstitution, structural model, or targeted mutagenesis of Pgt1 — has been characterized in the available corpus.","teleology":[{"year":2001,"claim":"It was unknown whether P. falciparum capped its mRNA using a metazoan-type fused capping enzyme or a yeast-type multi-protein system; characterizing the capping apparatus established that Pgt1 is a stand-alone guanylyltransferase separate from the triphosphatase, defining the parasite's capping architecture as yeast-like.","evidence":"Biochemical and sequence/functional characterization of the P. falciparum mRNA-capping apparatus identifying Pgt1 as the guanylyltransferase and Prt1 as a separate triphosphatase","pmids":["11248030"],"confidence":"Medium","gaps":["No in vitro reconstitution or mutagenesis of Pgt1 itself reported in this finding","The catalytic mechanism and active-site residues of Pgt1 are not defined","Whether Pgt1 and Prt1 physically associate into a complex is not established"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":null,"claim":"Whether Pgt1 acts within a defined multi-subunit capping complex, its structural basis for guanylyltransfer, and its essentiality for parasite viability remain uncharacterized in the available corpus.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of Pgt1","No genetic essentiality or knockdown data for Pgt1","No reconstituted capping assay assigning specific steps to Pgt1"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["P. falciparum mRNA-capping apparatus (two-component, yeast-like: guanylyltransferase Pgt1 + triphosphatase Prt1)"],"partners":["PRT1 (RNA TRIPHOSPHATASE, FUNCTIONALLY SEPARATE COMPONENT OF THE CAPPING APPARATUS)"],"other_free_text":["Pgt1 is the guanylyltransferase subunit alpha; the two capping activities are carried out by separate proteins, resembling the fungal/yeast rather than metazoan capping enzyme [#0]."]}},"prefetch_data":{},"corpus_meta":[{"pmid":"11248030","id":"PMC_11248030","title":"A yeast-like mRNA capping apparatus in Plasmodium falciparum.","date":"2001","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/11248030","citation_count":40,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["Pgt1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":3202,"output_tokens":445,"usd":0.008141,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":4961,"output_tokens":1249,"usd":0.028015,"stage2_stop_reason":"end_turn"},"total_usd":0.036156,"stage1_batch_id":"msgbatch_011BPjN2BL33F8cJXD1r7V7T","stage2_batch_id":"msgbatch_01Qwg6vP7qxkpL6Gsc7tajsb","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2001,\n      \"finding\": \"PF3D7_1414600 (Pgt1) encodes a separate RNA guanylyltransferase enzyme in P. falciparum, functioning as the mRNA-capping guanylyltransferase subunit alpha, distinct from the RNA triphosphatase (Prt1) component. The two activities are carried out by separate proteins (not fused), resembling the fungal/yeast capping apparatus rather than the metazoan one.\",\n      \"method\": \"Biochemical analysis and sequence/functional characterization of the P. falciparum mRNA capping apparatus, identifying Pgt1 as the guanylyltransferase and Prt1 as the triphosphatase as separate enzymes\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — functional characterization from a single lab identifying enzymatic activity and establishing the two-subunit architecture, but abstract does not detail in vitro reconstitution or mutagenesis for Pgt1 specifically\",\n      \"pmids\": [\"11248030\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"current_model\": \"PF3D7_1414600 (Pgt1) is the RNA guanylyltransferase subunit of the P. falciparum mRNA-capping apparatus, functioning as a separate enzyme from the RNA triphosphatase (Prt1) in a yeast-like two-component capping system rather than the fused metazoan-type enzyme.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PF3D7_1414600 (Pgt1) is the RNA guanylyltransferase of the Plasmodium falciparum mRNA-capping apparatus, functioning as the guanylyltransferase subunit alpha that is physically distinct from the RNA triphosphatase component (Prt1) [#0]. This two-component organization, in which the triphosphatase and guanylyltransferase activities are carried out by separate proteins rather than a single fused polypeptide, resembles the fungal/yeast capping system rather than the metazoan-type enzyme [#0]. Beyond this identification of Pgt1 as the separate guanylyltransferase subunit, no further mechanistic detail — in vitro reconstitution, structural model, or targeted mutagenesis of Pgt1 — has been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"It was unknown whether P. falciparum capped its mRNA using a metazoan-type fused capping enzyme or a yeast-type multi-protein system; characterizing the capping apparatus established that Pgt1 is a stand-alone guanylyltransferase separate from the triphosphatase, defining the parasite's capping architecture as yeast-like.\",\n      \"evidence\": \"Biochemical and sequence/functional characterization of the P. falciparum mRNA-capping apparatus identifying Pgt1 as the guanylyltransferase and Prt1 as a separate triphosphatase\",\n      \"pmids\": [\"11248030\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No in vitro reconstitution or mutagenesis of Pgt1 itself reported in this finding\",\n        \"The catalytic mechanism and active-site residues of Pgt1 are not defined\",\n        \"Whether Pgt1 and Prt1 physically associate into a complex is not established\"\n      ],\n      \"attribution\": [\n        {\n          \"species\": \"Plasmodium falciparum\",\n          \"strain\": \"\"\n        }\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Whether Pgt1 acts within a defined multi-subunit capping complex, its structural basis for guanylyltransfer, and its essentiality for parasite viability remain uncharacterized in the available corpus.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No structural model of Pgt1\",\n        \"No genetic essentiality or knockdown data for Pgt1\",\n        \"No reconstituted capping assay assigning specific steps to Pgt1\"\n      ],\n      \"attribution\": [\n        {\n          \"species\": \"Plasmodium falciparum\",\n          \"strain\": \"\"\n        }\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0004484\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [],\n    \"pathway\": [\n      {\"term_id\": \"GO:0006370\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"complexes\": [\n      \"P. falciparum mRNA-capping apparatus (two-component, yeast-like: guanylyltransferase Pgt1 + triphosphatase Prt1)\"\n    ],\n    \"partners\": [\n      \"Prt1 (RNA triphosphatase, functionally separate component of the capping apparatus)\"\n    ],\n    \"other_free_text\": [\n      \"Pgt1 is the guanylyltransferase subunit alpha; the two capping activities are carried out by separate proteins, resembling the fungal/yeast rather than metazoan capping enzyme [#0].\"\n    ]\n  }\n}","audit_flag":null,"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_1414600","name":null,"product":"mRNA-capping enzyme subunit alpha","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PbANKA","gene_id":"PBANKA_1028100","name":null,"product":"mRNA-capping enzyme subunit alpha, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PkH","gene_id":"PKNH_1343500","name":null,"product":"mRNA-capping enzyme subunit alpha, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"Pgt1","evaluation":null}