{"id":"a6d012a3-4d61-5280-8eee-174a40008a8b","stable_key":"59b18080-c560-563d-abc5-bac4ee82a27c:ergothioneine-egtd-sam","predicate":"donates_methyl_groups_via","statement":"Mycobacterium smegmatis EgtD uses SAM-dependent methyl transfer to convert histidine into hercynine.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"c04ea14b-199c-59c4-9250-6a19c034e4fd","mechanism_event_label":"The microbial synthesis branch connects to methyl-donor chemistry.","subject":{"id":"825f2da2-01bc-5874-a3c6-64f5ac867db5","slug":"s-adenosylmethionine","display_name":"S-Adenosyl-L-methionine","entity_type_key":"small_molecule"},"object":{"id":"cae59e2e-148f-5889-82fc-fb3d6632b719","slug":"mycobacterium-smegmatis-egtd","display_name":"Mycobacterium smegmatis EgtD","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"c04ea14b-199c-59c4-9250-6a19c034e4fd","stable_key":"59b18080-c560-563d-abc5-bac4ee82a27c:ergothioneine-egtd-sam-event","event_type":"observed_relationship","label":"The microbial synthesis branch connects to methyl-donor chemistry.","description":"Mycobacterium smegmatis EgtD uses SAM-dependent methyl transfer to convert histidine into hercynine.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"825f2da2-01bc-5874-a3c6-64f5ac867db5","slug":"s-adenosylmethionine","display_name":"S-Adenosyl-L-methionine","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"cae59e2e-148f-5889-82fc-fb3d6632b719","slug":"mycobacterium-smegmatis-egtd","display_name":"Mycobacterium smegmatis EgtD","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"939c92c3-50ea-5a4a-9654-8e3b94448132","slug":"ergothioneine","display_name":"L-Ergothioneine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"b3583649-cbbd-50f1-be33-26b1ee0dd6ab","slug":"hercynine","display_name":"Hercynine / N-alpha-trimethylhistidine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"44374451-3436-5136-a8ae-5dcc6d8c353b","slug":"histidine","display_name":"L-Histidine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"e84829b1-0607-558e-8add-aaa3af4747e7","slug":"s-adenosylhomocysteine","display_name":"S-Adenosyl-L-homocysteine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Apo and ligand-bound enzyme structures.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"No evidence that human ergothioneine consumption drains SAM; humans lack this established synthesis pathway.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Ergothioneine collection; molecular form, preparation, species, exposure and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"ergothioneine","display_name":"L-Ergothioneine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"The microbial synthesis branch connects to methyl-donor chemistry.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Structural insights into the histidine trimethylation activity of EgtD from Mycobacterium smegmatis. · 2014 · https://pubmed.ncbi.nlm.nih.gov/25251321/ · DOI 10.1016/j.bbrc.2014.09.058","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"3b1f5eb3-db2c-5f4b-b194-5f414b085631","evidence_kind":"source_excerpt","locator":"Lines 552-558","start_line":552,"end_line":558,"excerpt":"## ergothioneine-egtd-sam\nThe microbial synthesis branch connects to methyl-donor chemistry.\nMycobacterium smegmatis EgtD uses SAM-dependent methyl transfer to convert histidine into hercynine.\nModel: Apo and ligand-bound enzyme structures.\nLimitations: No evidence that human ergothioneine consumption drains SAM; humans lack this established synthesis pathway.\nEvidence access: Primary abstract\nStructural insights into the histidine trimethylation activity of EgtD from Mycobacterium smegmatis. · 2014 · https://pubmed.ncbi.nlm.nih.gov/25251321/ · DOI 10.1016/j.bbrc.2014.09.058","model_system":"Apo and ligand-bound enzyme structures.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; evidence access and experimental limitations specified.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"2f037d98-f3d0-5dbe-80d8-90b738f130d6","stable_key":"import-59b18080-c560-563d-abc5-bac4ee82a27c","title":"Ergothioneine: transport, redox chemistry and cross-nutrient mechanisms (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text.","file_path":"","sha256":"b6def8119f03cfabeec2fb55ba924340dc612e1dd42f05404201fa2b7ced5259","revision_id":"f88c38e6-ffb5-5a68-83ca-4610ca2c2df4","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}