Abstract
Eastern and western Taiwan Cobra (Naja atra) have been shown differences in morphology and toxicity, but the venomous components between them still remain obscure. Here we used two dimensional (Cation exchange and Reverse pharse) high performance liquid chromatography (2D-HPLC) and electrospray ionization mass spectrometry (ESI-MS) to identify and compare the venomous components between eastern and western Taiwan cobra. Molecular weight of 40 venomous proteins were determined, 12 of them were identified. A new cysteine-rich secretory protein (CRISP) with 24940 M.W. was first time found in this study. The N-terminal sequencing of this protein showed that it is highly homologous to ophanin, a CRISP isolated from king Cobra (Ophiophagus hannah) venom. Amount of this protein in crude venom is about 4-5% and showed constant expression in all Taiwan cobra. The proportions of cardiotoxin homologues were shown significantly different between eastern and western Taiwan cobra venoms. Analysis of eastern and western individual Taiwan cobra venomous components by high performance cation exchange liquid chromatography revealed cardiotoxin homologues A2 and A4 but not A6 are shown unique rich in western Taiwan cobra, the opposite result are observed in eastern Taiwan cobra. These results indicate that cardiotoxin homologues A2, A4 and A6 could become the key markers to distinguish eastern and western Taiwan cobra. In this study, we also found the northern Taiwan cobra whose morphology similar to eastern Taiwan cobra expressed both eastern and western Taiwan cobra cardiotoxin key markers. These results indicate the expression of unique cardiotoxin homologues in different geographical location might due to ecological causes.