{"id":"78160453-119c-59de-a5f9-f7b7212effaa","stable_key":"46d15d9e-d3b5-544d-ba01-b785aa3e4f42:b1-slc19a3-phosphorylation-binding-boundary","predicate":"interacts-less-strongly-with","statement":"Phosphorylated thiamine derivatives stabilized purified human SLC19A3 less strongly than free thiamine in binding assays.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"0ff829ed-4c09-5e49-a8b9-e030f1928c70","mechanism_event_label":"Adding phosphates changes how B1 fits this cell-surface carrier.","subject":{"id":"187db168-8028-5ce6-9f8b-4bc61ebad1a0","slug":"thiamine-diphosphate","display_name":"Thiamine diphosphate","entity_type_key":"small_molecule"},"object":{"id":"4eba176e-17c8-5515-920a-df5d48a40486","slug":"slc19a3","display_name":"Human thiamine transporter 2 / SLC19A3","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"0ff829ed-4c09-5e49-a8b9-e030f1928c70","stable_key":"46d15d9e-d3b5-544d-ba01-b785aa3e4f42:b1-slc19a3-phosphorylation-binding-boundary-event","event_type":"biochemical_relationship","label":"Adding phosphates changes how B1 fits this cell-surface carrier.","description":"Phosphorylated thiamine derivatives stabilized purified human SLC19A3 less strongly than free thiamine in binding assays.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"36b7c3eb-068b-500f-af1c-078829df1ecc","slug":"thiamine","display_name":"Thiamine (vitamin B1)","entity_type_key":"small_molecule"},"role":"reference ligand","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"2d52919c-025a-5772-92b0-6229c0b74ba3","slug":"thiamine-monophosphate","display_name":"Thiamine monophosphate","entity_type_key":"small_molecule"},"role":"phosphorylated comparator","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"187db168-8028-5ce6-9f8b-4bc61ebad1a0","slug":"thiamine-diphosphate","display_name":"Thiamine diphosphate","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"4eba176e-17c8-5515-920a-df5d48a40486","slug":"slc19a3","display_name":"Human thiamine transporter 2 / SLC19A3","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"evidence-scope","value_text":"Purified membrane protein","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_locator","value_text":"Results: cryo-EM structures; Supplementary Figure 1a","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_spans","value_text":"[{\"source_document\": \"artifacts/thiamine_transport_sources/PMC11447181.txt\", \"start_char\": 9508, \"end_char\": 11196}]","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Recombinant human SLC19A3 from Expi293F; cryo-EM and thermal-shift binding assays.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Thermal stabilization is not a direct transport-rate measurement.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Thiamine research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"thiamine","display_name":"Thiamine (vitamin B1)","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Adding phosphates changes how B1 fits this cell-surface carrier.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[gabriel-2024-slc19a3-structure] Structural basis of thiamine transport and drug recognition by SLC19A3 (2024). https://pmc.ncbi.nlm.nih.gov/articles/PMC11447181/ DOI: 10.1038/s41467-024-52872-8","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Purified membrane protein","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"dbbcedeb-ce6c-519f-979f-cc84083e3543","evidence_kind":"source_excerpt","locator":"Lines 588-600","start_line":588,"end_line":600,"excerpt":"### b1-slc19a3-phosphorylation-binding-boundary\nPhosphorylated thiamine derivatives stabilized purified human SLC19A3 less strongly than free thiamine in binding assays.\nCondition category: normal\nnutrient_topic: Thiamine research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Adding phosphates changes how B1 fits this cell-surface carrier.\norganism: Homo sapiens\ntissue_or_cell_type: Purified membrane protein\nexperimental_model: Recombinant human SLC19A3 from Expi293F; cryo-EM and thermal-shift binding assays.\nlimitations: Thermal stabilization is not a direct transport-rate measurement.\nevidence_spans: [{\"source_document\": \"artifacts/thiamine_transport_sources/PMC11447181.txt\", \"start_char\": 9508, \"end_char\": 11196}]\nevidence_locator: Results: cryo-EM structures; Supplementary Figure 1a\nevidence-scope: Purified membrane protein\n[gabriel-2024-slc19a3-structure] Structural basis of thiamine transport and drug recognition by SLC19A3 (2024). https://pmc.ncbi.nlm.nih.gov/articles/PMC11447181/ DOI: 10.1038/s41467-024-52872-8","model_system":"Recombinant human SLC19A3 from Expi293F; cryo-EM and thermal-shift binding assays.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [gabriel-2024-slc19a3-structure] Structural basis of thiamine transport and drug recognition by SLC19A3 (2024). https://pmc.ncbi.nlm.nih.gov/articles/PMC11447181/ DOI: 10.1038/s41467-024-52872-8","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"158d2c03-ac8c-589f-8270-c468165ae346","stable_key":"import-46d15d9e-d3b5-544d-ba01-b785aa3e4f42","title":"Thiamine: 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":"f376512fb3310141315548015b387833e3af45146e73fb73cd02cee20e4ddb9c","revision_id":"53bc5eda-dec8-58cc-a56f-a9eb4ab036ef","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}