Abstract
Cardiotoxin VI (CTX A6) is one component of Taiwan cobra venom. Cardiotoxin is different from component of Taiwan cobra venom between eastern and western Taiwan cobra. And CTX A6 is from eastern Taiwan cobra. In this study, we have found (1) From the crystal structure of CTX A6, Pro8 and Pro9 at loop I in CTX A6 and Tγ appear to have the same cis- conformation, but the structures of Pro8 and Pro9 at loop I in CTX A6 is different from the NMR structure of CTX Tγ. The difference of the structures of Pro8 and Pro9 at loop I in CTX A6 and Tγ may affect the interaction of Cardiotoxins and membrane. (2) In the crystal structure of CTX A6, there are two bound waters in loop II forming three hydrogen bonds. In other Cardiotoxins(CTX A3、Tγ、A5、O2), there are also bound waters in loop II. (3) In crystal packing of CTX A6 and Tγ, there are some similarities in terms of trimer orientation. Therefore, these findings from the crystal structure of CTX A6 at high-resolution 1.6Å may imply the interaction between Cardiotoxins and membrane.