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==Overview==

The serine proteinase alpha-thrombin plays a pivotal role in the, regulation of blood fluidity, and therefore constitutes a primary target, in the treatment of various haemostatic disorders. Haemadin is a slow, tight- binding thrombin inhibitor from the land-living leech Haemadipsa, sylvestris. Here we present the 3.1 A crystal structure of the human, alpha-thrombin- haemadin complex. The N-terminal segment of haemadin binds, to the active site of thrombin, forming a parallel beta-strand with, residues Ser214-Gly216 of the proteinase. This mode of binding is similar, to that observed in another leech-derived inhibitor, hirudin. In contrast, to hirudin, however, the markedly acidic C-terminal peptide of haemadin, does not bind the fibrinogen-recognition exosite, but interacts with the, heparin-binding exosite of thrombin. Thus, haemadin binds to thrombin, according to a novel mechanism, despite an overall structural similarity, with hirudin. Haemadin inhibits both free and thrombomodulin-bound, alpha-thrombin, but not intermediate activation forms such as, meizothrombin. This specific anticoagulant ability of haemadin makes it an, ideal candidate for an antithrombotic agent, as well as a starting point, for the design of novel antithrombotics.

The serine proteinase alpha-thrombin plays a pivotal role in the regulation of blood fluidity, and therefore constitutes a primary target in the treatment of various haemostatic disorders. Haemadin is a slow tight- binding thrombin inhibitor from the land-living leech Haemadipsa sylvestris. Here we present the 3.1 A crystal structure of the human alpha-thrombin- haemadin complex. The N-terminal segment of haemadin binds to the active site of thrombin, forming a parallel beta-strand with residues Ser214-Gly216 of the proteinase. This mode of binding is similar to that observed in another leech-derived inhibitor, hirudin. In contrast to hirudin, however, the markedly acidic C-terminal peptide of haemadin does not bind the fibrinogen-recognition exosite, but interacts with the heparin-binding exosite of thrombin. Thus, haemadin binds to thrombin according to a novel mechanism, despite an overall structural similarity with hirudin. Haemadin inhibits both free and thrombomodulin-bound alpha-thrombin, but not intermediate activation forms such as meizothrombin. This specific anticoagulant ability of haemadin makes it an ideal candidate for an antithrombotic agent, as well as a starting point for the design of novel antithrombotics.

==Disease==

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[[Category: coagulation/crystal structure/heparin-binding site/ hirudin/thrombin inhibitor]]

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@@ Line 4: / Line 4: @@
 ==Overview==
-The serine proteinase alpha-thrombin plays a pivotal role in the, regulation of blood fluidity, and therefore constitutes a primary target, in the treatment of various haemostatic disorders. Haemadin is a slow, tight- binding thrombin inhibitor from the land-living leech Haemadipsa, sylvestris. Here we present the 3.1 A crystal structure of the human, alpha-thrombin- haemadin complex. The N-terminal segment of haemadin binds, to the active site of thrombin, forming a parallel beta-strand with, residues Ser214-Gly216 of the proteinase. This mode of binding is similar, to that observed in another leech-derived inhibitor, hirudin. In contrast, to hirudin, however, the markedly acidic C-terminal peptide of haemadin, does not bind the fibrinogen-recognition exosite, but interacts with the, heparin-binding exosite of thrombin. Thus, haemadin binds to thrombin, according to a novel mechanism, despite an overall structural similarity, with hirudin. Haemadin inhibits both free and thrombomodulin-bound, alpha-thrombin, but not intermediate activation forms such as, meizothrombin. This specific anticoagulant ability of haemadin makes it an, ideal candidate for an antithrombotic agent, as well as a starting point, for the design of novel antithrombotics.
+The serine proteinase alpha-thrombin plays a pivotal role in the regulation of blood fluidity, and therefore constitutes a primary target in the treatment of various haemostatic disorders. Haemadin is a slow tight- binding thrombin inhibitor from the land-living leech Haemadipsa sylvestris. Here we present the 3.1 A crystal structure of the human alpha-thrombin- haemadin complex. The N-terminal segment of haemadin binds to the active site of thrombin, forming a parallel beta-strand with residues Ser214-Gly216 of the proteinase. This mode of binding is similar to that observed in another leech-derived inhibitor, hirudin. In contrast to hirudin, however, the markedly acidic C-terminal peptide of haemadin does not bind the fibrinogen-recognition exosite, but interacts with the heparin-binding exosite of thrombin. Thus, haemadin binds to thrombin according to a novel mechanism, despite an overall structural similarity with hirudin. Haemadin inhibits both free and thrombomodulin-bound alpha-thrombin, but not intermediate activation forms such as meizothrombin. This specific anticoagulant ability of haemadin makes it an ideal candidate for an antithrombotic agent, as well as a starting point for the design of novel antithrombotics.
 ==Disease==
@@ Line 27: / Line 27: @@
 [[Category: coagulation/crystal structure/heparin-binding site/ hirudin/thrombin inhibitor]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb  3 09:36:26 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:22:25 2008''