{"id":"ebb63c3e-7b36-53cc-a0f6-39df522f0fe6","stable_key":"1310afbd-6010-586e-805d-551d846da421:b6-neuro-ddc-plp-conformation","predicate":"changes-conformation-of","statement":"Human apoDDC has exposed active sites; PLP-titrated structures and kinetics support a cofactor-linked conformational transition.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"dae5ef66-280d-5b23-9231-2f6da94ec872","mechanism_event_label":"Cofactor binding changes the enzyme structure.","subject":{"id":"6b656ff5-9532-5da4-8eea-8ca163a48649","slug":"pyridoxal-phosphate","display_name":"PLP","entity_type_key":"small_molecule"},"object":{"id":"cdc3fa8b-c680-5b62-bac0-f4d9b3baed95","slug":"ddc","display_name":"Human aromatic L-amino acid decarboxylase / DDC","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"dae5ef66-280d-5b23-9231-2f6da94ec872","stable_key":"1310afbd-6010-586e-805d-551d846da421:b6-neuro-ddc-plp-conformation-event","event_type":"biochemical_relationship","label":"Cofactor binding changes the enzyme structure.","description":"Human apoDDC has exposed active sites; PLP-titrated structures and kinetics support a cofactor-linked conformational transition.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"6b656ff5-9532-5da4-8eea-8ca163a48649","slug":"pyridoxal-phosphate","display_name":"PLP","entity_type_key":"small_molecule"},"role":"cofactor","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"cdc3fa8b-c680-5b62-bac0-f4d9b3baed95","slug":"ddc","display_name":"Human aromatic L-amino acid decarboxylase / DDC","entity_type_key":"protein"},"role":"enzyme","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"experimental_model","value_text":"Purified human DDC crystallography and kinetics","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Apoenzyme crystallization and varied crystal PLP concentrations.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"The closed comparison included pig holoenzyme; proposed degradation consequences were not directly established.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-b6","display_name":"Vitamin B6","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Cofactor binding changes the enzyme structure.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[giardina-2011-ddc] Open conformation of human DOPA decarboxylase reveals the mechanism of PLP addition to Group II decarboxylases (2011). https://pmc.ncbi.nlm.nih.gov/articles/PMC3251144/ DOI: 10.1073/pnas.1111456108","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Purified recombinant protein; no intact tissue","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"3d23e283-3aa6-5ab3-bd32-970b20c2f704","evidence_kind":"source_excerpt","locator":"Lines 1023-1033","start_line":1023,"end_line":1033,"excerpt":"### b6-neuro-ddc-plp-conformation\nHuman apoDDC has exposed active sites; PLP-titrated structures and kinetics support a cofactor-linked conformational transition.\nCondition category: normal\nnutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Cofactor binding changes the enzyme structure.\norganism: Homo sapiens\ntissue_or_cell_type: Purified recombinant protein; no intact tissue\nexperimental_model: Purified human DDC crystallography and kinetics\nlimitations: The closed comparison included pig holoenzyme; proposed degradation consequences were not directly established.\nexposure: Apoenzyme crystallization and varied crystal PLP concentrations.\n[giardina-2011-ddc] Open conformation of human DOPA decarboxylase reveals the mechanism of PLP addition to Group II decarboxylases (2011). https://pmc.ncbi.nlm.nih.gov/articles/PMC3251144/ DOI: 10.1073/pnas.1111456108","model_system":"Purified human DDC crystallography and kinetics","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [giardina-2011-ddc] Open conformation of human DOPA decarboxylase reveals the mechanism of PLP addition to Group II decarboxylases (2011). https://pmc.ncbi.nlm.nih.gov/articles/PMC3251144/ DOI: 10.1073/pnas.1111456108","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"251773bb-16f5-5903-b135-db4a61d9dec4","stable_key":"import-1310afbd-6010-586e-805d-551d846da421","title":"Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"ef0019b344b2219220f801a84d0d138ff6880c1be1a59540d9034bfa4334f61e","revision_id":"cac3555f-48af-5c52-a84e-add4482c87fb","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}