biostudies-literatureVadivel KAustrian Science Fund FWFNHLBI NIH HHSNational Heart, Lung, and Blood Institute809-819https://www.ebi.ac.uk/biostudies/studies/S-EPMC8171065biostudies-literatureUnknown77(Pt 6)Coagulation factor VIIa (FVIIa) consists of a γ-carboxyglutamic acid (GLA) domain, two epidermal growth factor-like (EGF) domains and a protease domain. FVIIa binds three Mg²⁺ ions and four Ca²⁺ ions in the GLA domain, one Ca²⁺ ion in the EGF1 domain and one Ca²⁺ ion in the protease domain. Further, FVIIa contains an Na⁺ site in the protease domain. Since Na⁺ and water share the same number of electrons, Na⁺ sites in proteins are difficult to distinguish from waters in X-ray structures. Here, to verify the Na⁺ site in FVIIa, the structure of the FVIIa-soluble tissue factor (TF) complex was solved at 1.8 Å resolution containing Mg²⁺, Ca²⁺ and Rb⁺ ions. In this structure, Acta crystallographica. Section D, Structural biologyStructure of human factor VIIa-soluble tissue factor with calcium, magnesium and rubidium.PMC8171065R01 HL141850R01HL141850P01 HL139420P01HL139420W1213Vadivel KKrishnaswamy SPadmanabhan KCascio DBrandstetter HBajaj SPSchmidt AEfalseStructure of human factor VIIa-soluble tissue factor with calcium, magnesium and rubidium.Coagulation factor VIIa (FVIIa) consists of a γ-carboxyglutamic acid (GLA) domain, two epidermal growth factor-like (EGF) domains and a protease domain. FVIIa binds three Mg²⁺ ions and four Ca²⁺ ions in the GLA domain, one Ca²⁺ ion in the EGF1 domain and one Ca²⁺ ion in the protease domain. Further, FVIIa contains an Na⁺ site in the protease domain. Since Na⁺ and water share the same number of electrons, Na⁺ sites in proteins are difficult to distinguish from waters in X-ray structures. Here, to verify the Na⁺ site in FVIIa, the structure of the FVIIa-soluble tissue factor (TF) complex was solved at 1.8 Å resolution containing Mg²⁺, Ca²⁺ and Rb⁺ ions. In this structure, 2021-01-01T00:00:00Z2021 Jun2025-04-25T16:52:29.023Z2025-02-18T23:32:14.746ZS-EPMC81710653407659410.1107/S205979832100392210.1107/s2059798321003922