Integrin alphaIIbbeta3 of the platelet surfaces regulates the thrombosis formation. alphaIIbbeta3 binds to the RGD sequence (Arg-Gly-Asp) of fibrinogen, promotes the platelet aggregation and finally leads to the thrombus. We obtained the three-dimensional molecular structure of alphaIIbbeta3 using homology-modeling (modeller8v2 software), with integrin alphavbeta3 (pdb code 1JV2) as the template. Accordingly, a cyclic RGD(RGD-c) peptide was designed to bind alphaIIbbeta3 as an antagonist and to block the formation of thrombus. We added two amino acids X, Y to both sides of RGD-c. X and Y could bind to each other by disulfide bond that finally made RGD-c a cyclic peptide. The optimum structure of RGD-c was obtained from the energetic optimization processes. All amino acids were placed at the X and Y to conduct Molecular Docking to the integrin alphaIIbbeta3 We got the optimum structure of RGD-c by energetic optimization and the antagonistic combination analysis. The results might provide an insight into designing and screening integrin alphaIIbbeta3 antagonists.
Amino Acid Sequence ; Drug Design ; Humans ; Models, Molecular ; Oligopeptides ; chemistry ; Platelet Aggregation Inhibitors ; chemical synthesis ; chemistry ; Platelet Glycoprotein GPIIb-IIIa Complex ; antagonists & inhibitors ; chemistry