Antithrombin III: structural and functional aspects

Abstract : Antithrombin Ill is a plasma glycoprotein responsib!e for thrombin inhibition in the blood coagulation cascade. The X-ray structure of its cleaved form has been determined and refined to 3.2 A resolution. The overall topology is similar to that of 6,rantitrypsin, anothe ~. member of the serpin (serine protease inhibitor) superfamily. The biological activity of antithrombin III is mediated by a polysaccharide, heparir. The binding site of this effector is described. A possible structural transition from the native to the cleaved structure is discussed. antithrombin !I1 / X.ray structure / heparin / serpin superfamily