A new gene structure of disintegrin family: a subunit of dimeric disintegrin has short coding region

Abstract number: P1756

Morita^* T., Okuda^* D., Koike^* H.

^*Meiji Pharmaceutical University, Japan

Disintegrins with ~80 amino acid residues are potent platelet aggregation inhibitors derived from snake venom. They have Arg-Gly-Asp (RGD) or Lys-Gly-Asp (KGD) sequence in their amino acid sequence for the binding motif to several integrins, such as platelet GPIIb/IIIa (integrin a IIbb 3) complex. Over the past years, around 40 disintegrins have been isolated and characterized from many snake venoms. However, the cDNA cloning of only a few disintegrins has been reported so far. Interestingly, venom disintegrins are encoded with a prepeptide, metalloprotease and disintegrin region on their common precursor. It is suggested that the metalloprotease/disintegrin precursor is cleaved by protease(s) resulting in production of metalloprotease and disintegrin. Many venom metalloproteases also contain a disintegrin-like domain with no RGD or KGD sequence, and a cysteine(Cys)-rich domain in those structures. The metalloprotease/disintegrin (/Cys-rich) domain structures are commonly distributed in reptiles and mammals. This disintegrin-like domain is found in the mammalian ADAM (A Disintegrin and Metalloprotease) family proteins such as MDC9, fertilin-a and TACE (TNF-a converting enzyme), and ADAM-TS (thrombospondin) family proteins such as aggrecanase-1, -2, indicating that the disintegrin-like domain is involved in cell–matrix interaction. We recently reported a novel heterodimeric disintegrin, piscivostatin from the venom of Agkistrodon piscivorus pircivorus. Piscivostatin has a unique effect on platelet aggregation, which inhibits platelet aggregation and platelets aggregates dissociation. In this study, we show that the purification of another heterodimeric disintegrin, acostatin from the venom of Agkistrodon contortrix contortrix and the cDNA cloning of these two heterodimeric disintegrins. Both subunits of acostatin and piscivostatin have apparently different-length mature protein-coding regions from the other members of the venom metalloprotease/disintegrin family. One of two subunits in acostatin and piscivostatin has a shorter length cDNA than other members of venom metalloprotease/disintegrin family. This is the first report of the cDNA cloning of heterodimeric disintegrin and a novel domain structure of the disintegrin family gene.