THE CRYSTAL-STRUCTURE OF THE COMPLEX OF BLOOD-COAGULATION FACTOR VIIAWITH SOLUBLE TISSUE FACTOR

Blood coagulation is initiated when tissue factor binds to coagulation factor VIIa to give an enzymatically active complex which then activa tes factors IX and X, leading too thrombin generation and clot formati on. We have determined the crystal structure at 2.0-Angstrom resolutio n of active-site-inhibited factor VIIa complexed with the cleaved extr acellular domain of tissue factor. In the complex, factor VIIa adopts an extended conformation. This structure provides a basis for understa nding many molecular aspects of the initiation of coagulation.