{"id":"957548e9-572c-5c10-b409-2b76cc30ac5e","stable_key":"1310afbd-6010-586e-805d-551d846da421:b6-neuro-spt-plp-site","predicate":"binds","statement":"Human SPT structures place PLP at the SPTLC1-SPTLC2 interface, with the catalytic lysine supplied by SPTLC2.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"e0d6d9b9-fd05-5378-8333-505b64499392","mechanism_event_label":"SPT uses activated B6 where its two core subunits meet.","subject":{"id":"6b656ff5-9532-5da4-8eea-8ca163a48649","slug":"pyridoxal-phosphate","display_name":"PLP","entity_type_key":"small_molecule"},"object":{"id":"398222a2-74f5-5eb7-bf2f-bf5f75b6fd7d","slug":"sptlc2","display_name":"Human serine palmitoyltransferase long-chain base subunit 2","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"e0d6d9b9-fd05-5378-8333-505b64499392","stable_key":"1310afbd-6010-586e-805d-551d846da421:b6-neuro-spt-plp-site-event","event_type":"biochemical_relationship","label":"SPT uses activated B6 where its two core subunits meet.","description":"Human SPT structures place PLP at the SPTLC1-SPTLC2 interface, with the catalytic lysine supplied by SPTLC2.","status":"provisional","compartment":{"slug":"endoplasmic-reticulum","display_name":"Endoplasmic reticulum"},"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":"da1ba1a7-e457-5459-8e95-a2c405c3330c","slug":"sptlc1","display_name":"Human serine palmitoyltransferase long-chain base subunit 1","entity_type_key":"protein"},"role":"subunit","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"398222a2-74f5-5eb7-bf2f-bf5f75b6fd7d","slug":"sptlc2","display_name":"Human serine palmitoyltransferase long-chain base subunit 2","entity_type_key":"protein"},"role":"catalytic-subunit","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"6c38f454-a2e4-57eb-820c-9b51a9c3eb05","slug":"sptssa","display_name":"Human small subunit of serine palmitoyltransferase A","entity_type_key":"protein"},"role":"regulatory-subunit","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"experimental_model","value_text":"Recombinant human SPT complexes; cryo-EM and cell/microsome activity assays","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Cryo-EM of recombinant complexes.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"No dietary B6 manipulation.","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":"SPT uses activated B6 where its two core subunits meet.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[wang-2021-spt] Structural insights into the regulation of human serine palmitoyltransferase complexes (2021). https://pmc.ncbi.nlm.nih.gov/articles/PMC9812531/ DOI: 10.1038/s41594-020-00551-9","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":"5f1a13d9-2ec7-54f0-aa0e-c0f5c7dc2d55","evidence_kind":"source_excerpt","locator":"Lines 1108-1118","start_line":1108,"end_line":1118,"excerpt":"### b6-neuro-spt-plp-site\nHuman SPT structures place PLP at the SPTLC1-SPTLC2 interface, with the catalytic lysine supplied by SPTLC2.\nCondition category: normal\nnutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: SPT uses activated B6 where its two core subunits meet.\norganism: Homo sapiens\ntissue_or_cell_type: Purified recombinant protein; no intact tissue\nexperimental_model: Recombinant human SPT complexes; cryo-EM and cell/microsome activity assays\nlimitations: No dietary B6 manipulation.\nexposure: Cryo-EM of recombinant complexes.\n[wang-2021-spt] Structural insights into the regulation of human serine palmitoyltransferase complexes (2021). https://pmc.ncbi.nlm.nih.gov/articles/PMC9812531/ DOI: 10.1038/s41594-020-00551-9","model_system":"Recombinant human SPT complexes; 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Study references: [wang-2021-spt] Structural insights into the regulation of human serine palmitoyltransferase complexes (2021). https://pmc.ncbi.nlm.nih.gov/articles/PMC9812531/ DOI: 10.1038/s41594-020-00551-9","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}