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(2025). https://pubmed.ncbi.nlm.nih.gov/39880952/ DOI: 10.1038/s41586-024-08484-9","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Endoplasmic-reticulum membrane enzyme","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"66792671-44a3-5dec-bd74-182829d8f477","evidence_kind":"source_excerpt","locator":"Lines 370-381","start_line":370,"end_line":381,"excerpt":"### k2-ggcx-cofactor\nGGCX couples oxidation of reduced vitamin K to conversion of protein-bound glutamate into gamma-carboxyglutamate.\nCondition category: normal\nnutrient_topic: Vitamin K2 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Vitamin K helps an enzyme modify selected proteins; it does not carry calcium into bone itself.\norganism: Human GGCX\ntissue_or_cell_type: Endoplasmic-reticulum membrane enzyme\nexperimental_model: Cryo-EM, binding, cell assays and molecular dynamics\nlimitations: Shared vitamin K chemistry; the abstract does not establish K2 exclusivity or identical kinetics for every menaquinone.\nexposure: Apo, osteocalcin-bound and vitamin-K-bound structures\nevidence_span: {\"source_cache\": \"artifacts/k2-research/39880952.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"eb8e6d00eecd7c5c780921cae3f804fab60e919301eeb16e9909f36293aaa653\", \"start_char\": 0, \"end_char\": 1230, \"text_sha256\": \"eb8e6d00eecd7c5c780921cae3f804fab60e919301eeb16e9909f36293aaa653\"}\n[k2-p39880952] Structure and mechanism of vitamin-K-dependent γ-glutamyl carboxylase. 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