title: Ultrastructure of human coagulation factor V.
abstract: Purified single-chain human coagulation factor V (Mr approximately 330,000) was visualized by high-resolution transmission electron microscopy. The molecule was found to be composed of four major domains. Three similar sized (approximately 90 X 70 A) globular domains were linked via thin (approximately 30 A) spacers to a somewhat larger (approximately 165 X 138 A) central domain. The center-to-center distances between the larger central domain and each of the peripheral domains were found to be approximately 120 A. Incubation of factor V with thrombin resulted in a separation of the peripheral domains from the central domain. This indicates that the factor V domains now observed correspond to the previously characterized factor V fragments formed by limited proteolysis using thrombin. From these results, a model of the three-dimensional factor V structure, distinct from previous models, is proposed.
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002850:Chromatography, Gel; D005165:Factor V / Q000378:metabolism; D015943:Factor Va; D006801:Humans; D008854:Microscopy, Electron; D008970:Molecular Weight; D010446:Peptide Fragments / Q000378:metabolism; D013917:Thrombin / Q000378:metabolism
chemical_list: D010446:Peptide Fragments; D015943:Factor Va; D005165:Factor V; D013917:Thrombin