The factor VIIa/tissue factor complex.

The tissue factor:factor VIIa (TF:F.VIIa) complex is the physiological initiator of blood coagulation and plays a role both in normal hemostasis and in various thrombotic disorders. The TF:F.VIIa crystal structure presented here shows the two molecules in association as a complex and provides a ready structural explantation for most of the complementary observations on the complex obtained by other techniques. This is only one F.VII structure of a series along the activation pathway going from zymogen F.VII, through F.VIIa alone, towards that in the ternary complex with a macromolecular substrate such as F.IX or F.X. To fully understand the activation of F.VIIa by TF will require further structural work, but in the meantime this structure may be used in the search for more effective and more specific anticoagulants.