Expression and Functional Analysis of Disintegrin from Agkistrodon Actus Venom.

Disintegrin is a kind of small native peptides derived from the snake venom, containing RGD sequences. Its interaction with integrins, such as aIIbb3, anb3 and a5b1, can inhibit platelet aggregation. hinder the process of angiogenesis and tumor metastasis. In order to further investigate the function of disintegrin in platelet aggregation, cell adhesion and angiogenesis, the sequence encoding the disintegrin domain of agacutin was fused with enhanced green fluorencent protein(eGFP) and inserted in plasmid pQE-30. The recombinant protein was expressed in E.Coli M15 after induction by IPTG, amounting to 38% of the total bacterial protein. The cells expressing integrin such as breast cancer cell line MDA-MB-231 and endothelial cell line EA.hy926 can specifically bind to the recombinant GFP-disintegrin. Flow cytometry showed that the recombinant protein could bind to platelet specfically and could compete with anti-b3 integrin monoclonal antibody CD61. Moreover, the recombinant protein could inhibit platelet aggregation induced by collagen and ADP in a dose-dependent manner, but had no ability to impede the platelet aggregation induced by Ristocetin. Meanwhile, it could inhibit cell (MDA-MB-231 and EA.hy926) adhesion to fibronectin with inhibition rate of 69% and 48%, respectively. Finally, it could induce apoptosis of EA.hy926 endothelial cells and inhibit the angiogenesis on chicken chorioallantoic membrane mode. As a result, it is demonstrated that GFP-disintegrin has the combined quality of its disparate components and can serve as a novel tool for study of tumor and angiogenesis. In addition, the recombinant protein can efficiently inhibit platelet aggregation and angiogenesis, which will be useful for designing the potential drug for anti-thrombosis and anti-tumor metastasis.