Kistrin is a strong inhibitor of platelet aggregation and is a member of the GP IIb-IIIa protein antagonists known as disintegrins, which are found in snake venom. Kistrin was found in the venom of the Malayan pit viper Agkistrodon rhodostoma. Platelet aggregation occurs when the surface of a glycoprotein (GP) IIb-IIIa interacts with plasma protein, fibrinogen (Fg), which leads to the formation of platelet-rich clots. The fact that kistrin inhibits this aggregating process may be beneficial to patients who suffer from arterial thrombotic diseases.
GP IIb-IIIa is a member of a family of glycoproteins called integrins. Integrins are cell surface receptors that play a role in cell-matrix and cell-cell adhesion. Extracellular ligands such as fibrinogen , fibronectin, and vitronectin bind to integrins at the RGD (Arg-Gly-Asp) adhesion site recognition sequence thought to be important for binding. Kistrin contains an RGD site at residues 49, 50, and 51 which are shown in magenta. It binds to GP IIb-IIIa reversibly.
Kistrin is a 68 amino-acid residue protein that contains very little secondary structure and six intramolecular disulfide bonds which are shown in dark purple: Cys4-Cys19, Cys6-Cys14, Cys13-Cys36, Cys27-Cys33, Cys32-Cys57, and Cys45-Cys64.
- Keywords: Blood Coagulation, Platelet, Cell Adhesion, Venom
- View this protein's PDB entry as 1KST
- View this protein's SwissProt entry as DISI_AGKRH
M. Adler, R.A. Lazarus, M.S. Dennis, G. Wagner
Solution Structure of Kistrin, a Potent Platelet Aggregation Inhibitor and GP IIb-IIIa Antagonist.
Science 253:445 (1991)
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