ジャーナル: Biopolymers / 年: 2013 タイトル: Domain organization of membrane-bound factor VIII. 著者: Svetla Stoilova-McPhie / Gillian C Lynch / Steven Ludtke / B Montgomery Pettitt / 要旨: Factor VIII (FVIII) is the blood coagulation protein which when defective or deficient causes for hemophilia A, a severe hereditary bleeding disorder. Activated FVIII (FVIIIa) is the cofactor to the ...Factor VIII (FVIII) is the blood coagulation protein which when defective or deficient causes for hemophilia A, a severe hereditary bleeding disorder. Activated FVIII (FVIIIa) is the cofactor to the serine protease factor IXa (FIXa) within the membrane-bound Tenase complex, responsible for amplifying its proteolytic activity more than 100,000 times, necessary for normal clot formation. FVIII is composed of two noncovalently linked peptide chains: a light chain (LC) holding the membrane interaction sites and a heavy chain (HC) holding the main FIXa interaction sites. The interplay between the light and heavy chains (HCs) in the membrane-bound state is critical for the biological efficiency of FVIII. Here, we present our cryo-electron microscopy (EM) and structure analysis studies of human FVIII-LC, when helically assembled onto negatively charged single lipid bilayer nanotubes. The resolved FVIII-LC membrane-bound structure supports aspects of our previously proposed FVIII structure from membrane-bound two-dimensional (2D) crystals, such as only the C2 domain interacts directly with the membrane. The LC is oriented differently in the FVIII membrane-bound helical and 2D crystal structures based on EM data, and the existing X-ray structures. This flexibility of the FVIII-LC domain organization in different states is discussed in the light of the FVIIIa-FIXa complex assembly and function.
名称: 20 mM Tris-HCl, 150 mM NaCl, 5mM CaCl2 / pH: 7.4 / 詳細: 20 mM Tris-HCl, 150 mM NaCl, 5mM CaCl2
試料
濃度: 1 mg/ml / 包埋: NO / シャドウイング: NO / 染色: NO / 凍結: YES
試料支持
詳細: 300 mesh R2x2 Quantifoil grids
急速凍結
装置: FEI VITROBOT MARK III / 凍結剤: ETHANE / Temp: 95 K / 湿度: 100 % 詳細: Blot for 3.5 seconds before plunging into liquid ethane (Vitrobot Mark III) 手法: Blot for 3.5 seconds before plunging