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PubMed · 8082790

Structure of membrane-bound human factor Va.

S Stoylova·K G Mann·A Brisson
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Abstract

Coagulation factor Va is an essential cofactor which combines with the serine protease factor Xa on a phospholipid surface to form the prothrombinase complex. In the present study, the structure of factor Va interacting with lipid surfaces containing phosphatidylserine was studied by electron microscopy. Two-dimensional crystals of factor Va were obtained on planar lipid films under quasi-physiological conditions. The two-dimensional projected structure of factor Va was calculated at a resolution of 2 nm, revealing dimers of factor Va arranged on the surface lattice with the symmetry of the plane group p2. Average unit cell dimensions are a = 14.4 nm, b = 8.8 nm, gamma = 107 degrees. Each factor Va molecule presents two distinct domains of protein density consisting of one small domain, of 3 nm in diameter, connected to a larger domain of about 6 nm x 4.5 nm. The projected structure of factor Va covers an area equivalent to about fifty phospholipid molecules. In addition, edge-on views of factor Va molecules bound to liposomes reveal a globular structure connected through a thin stem to the liposome surface. A three-dimensional model of membrane-bound factor Va is proposed.

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Cell MembraneCrystallizationFactor VaHumansLiposomesMicroscopy, ElectronProtein BindingProtein ConformationJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.

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BibTeXRIS

S Stoylova, K G Mann, A Brisson. 1994-09-12. Structure of membrane-bound human factor Va.. https://doi.org/10.1016/0014-5793(94)00881-7

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