{"id":"514ab049-f68b-5b42-b5c6-41d8c9a3a2e9","stable_key":"1310afbd-6010-586e-805d-551d846da421:b6-transport-plpbp-r241q","predicate":"reduces-binding-of","statement":"Purified R241Q lacked detectable bound PLP, but a fourfold molar PLP excess produced a mixture including holo-protein.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"95e90685-c662-5162-b9c5-c25d71a0e22b","mechanism_event_label":"This variant binds poorly but is not absolutely incapable of binding.","subject":{"id":"a59498cc-58a6-5021-9e5f-d13a1f211d48","slug":"plpbp-r241q","display_name":"Human PLPBP Arg241Gln","entity_type_key":"protein_state"},"object":{"id":"6b656ff5-9532-5da4-8eea-8ca163a48649","slug":"pyridoxal-phosphate","display_name":"PLP","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"95e90685-c662-5162-b9c5-c25d71a0e22b","stable_key":"1310afbd-6010-586e-805d-551d846da421:b6-transport-plpbp-r241q-event","event_type":"biochemical_relationship","label":"This variant binds poorly but is not absolutely incapable of binding.","description":"Purified R241Q lacked detectable bound PLP, but a fourfold molar PLP excess produced a mixture including holo-protein.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"095f4f11-a415-519e-a0e2-d68cb617f397","slug":"plpbp","display_name":"Human PLP-binding protein / PLPBP","entity_type_key":"protein"},"role":"wild-type comparator","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"a59498cc-58a6-5021-9e5f-d13a1f211d48","slug":"plpbp-r241q","display_name":"Human PLPBP Arg241Gln","entity_type_key":"protein_state"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"6b656ff5-9532-5da4-8eea-8ca163a48649","slug":"pyridoxal-phosphate","display_name":"PLP","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"evidence_location","value_text":"Full text: biochemical properties and Figure 2B-D","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Recombinant human PLPBP and HEK293 proteomics.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Purification followed by PLP addition.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Biochemical reconstitution does not establish clinical rescue.","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":"This variant binds poorly but is not absolutely incapable of binding.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[fux2020] Biochemical and Proteomic Studies of Human Pyridoxal 5'-Phosphate-Binding Protein (PLPBP). (2020). https://pubmed.ncbi.nlm.nih.gov/31825581/ DOI: 10.1021/acschembio.9b00857","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Recombinant human protein","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"66234e24-4711-5594-ae6e-8541b80819bb","evidence_kind":"source_excerpt","locator":"Lines 400-411","start_line":400,"end_line":411,"excerpt":"### b6-transport-plpbp-r241q\nPurified R241Q lacked detectable bound PLP, but a fourfold molar PLP excess produced a mixture including holo-protein.\nCondition category: machinery_impairment\nnutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: This variant binds poorly but is not absolutely incapable of binding.\norganism: Homo sapiens\ntissue_or_cell_type: Recombinant human protein\nexperimental_model: Recombinant human PLPBP and HEK293 proteomics.\nlimitations: Biochemical reconstitution does not establish clinical rescue.\nexposure: Purification followed by PLP addition.\nevidence_location: Full text: biochemical properties and Figure 2B-D\n[fux2020] Biochemical and Proteomic Studies of Human Pyridoxal 5'-Phosphate-Binding Protein (PLPBP). (2020). https://pubmed.ncbi.nlm.nih.gov/31825581/ DOI: 10.1021/acschembio.9b00857","model_system":"Recombinant human PLPBP and HEK293 proteomics.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [fux2020] Biochemical and Proteomic Studies of Human Pyridoxal 5'-Phosphate-Binding Protein (PLPBP). (2020). https://pubmed.ncbi.nlm.nih.gov/31825581/ DOI: 10.1021/acschembio.9b00857","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}