{"id":"9ca23bf4-5799-5168-ba51-676a00d9bc41","stable_key":"41a89233-da9a-5b7b-9c18-e19bbadcfe2d:methionine-mat-magnesium","predicate":"coordinates","statement":"The human MAT2A inhibitor-bound structure contained two magnesium ions coordinating phosphate groups at the catalytic site.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"1c0326a6-997e-5e99-854d-6f52befc66af","mechanism_event_label":"SAM-making chemistry depends on correctly organized metal/phosphate contacts.","subject":{"id":"bff427ab-35f9-59c2-bb24-fd5953bbaec2","slug":"magnesium-ion","display_name":"Mg2+","entity_type_key":"ion"},"object":{"id":"bbc04455-e242-5f4d-9a6c-5b2ee6a6cb41","slug":"human-mat2a","display_name":"Human methionine adenosyltransferase 2A / MAT2A","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"1c0326a6-997e-5e99-854d-6f52befc66af","stable_key":"41a89233-da9a-5b7b-9c18-e19bbadcfe2d:methionine-mat-magnesium-event","event_type":"observed_relationship","label":"SAM-making chemistry depends on correctly organized metal/phosphate contacts.","description":"The human MAT2A inhibitor-bound structure contained two magnesium ions coordinating phosphate groups at the catalytic site.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"bff427ab-35f9-59c2-bb24-fd5953bbaec2","slug":"magnesium-ion","display_name":"Mg2+","entity_type_key":"ion"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"bbc04455-e242-5f4d-9a6c-5b2ee6a6cb41","slug":"human-mat2a","display_name":"Human methionine adenosyltransferase 2A / MAT2A","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"9d39f561-740b-5f67-bba7-8a72ef612a99","slug":"methionine","display_name":"L-Methionine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"58b974f1-d389-5bf6-81cd-889c44442c42","slug":"atp","display_name":"ATP","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"825f2da2-01bc-5874-a3c6-64f5ac867db5","slug":"s-adenosylmethionine","display_name":"S-Adenosyl-L-methionine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human MAT2A structure with nonhydrolyzable imidotriphosphate and methylthioadenosine.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Inhibitor-bound structural contacts are not a dietary magnesium dose-response.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Methionine collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"methionine","display_name":"L-Methionine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"SAM-making chemistry depends on correctly organized metal/phosphate contacts.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Mechanism and Inhibition of Human Methionine Adenosyltransferase 2A. · 2021 · https://pubmed.ncbi.nlm.nih.gov/33656855/ · DOI 10.1021/acs.biochem.0c00998","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"f31757c5-caf6-5221-94ef-00fbee12b04b","evidence_kind":"source_excerpt","locator":"Lines 132-138","start_line":132,"end_line":138,"excerpt":"## methionine-mat-magnesium\nSAM-making chemistry depends on correctly organized metal/phosphate contacts.\nThe human MAT2A inhibitor-bound structure contained two magnesium ions coordinating phosphate groups at the catalytic site.\nModel: Human MAT2A structure with nonhydrolyzable imidotriphosphate and methylthioadenosine.\nLimitations: Inhibitor-bound structural contacts are not a dietary magnesium dose-response.\nEvidence access: Primary abstract\nMechanism and Inhibition of Human Methionine Adenosyltransferase 2A. · 2021 · https://pubmed.ncbi.nlm.nih.gov/33656855/ · DOI 10.1021/acs.biochem.0c00998","model_system":"Human MAT2A structure with nonhydrolyzable imidotriphosphate and methylthioadenosine.","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":"d969b004-ccc2-5bb4-9109-8ac649137ad1","stable_key":"import-41a89233-da9a-5b7b-9c18-e19bbadcfe2d","title":"L-Methionine: transport, methylation, sulfur metabolism 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. 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