cDNA sequence analysis and expression of cardiotoxins from Taiwan Cobra

The cDNAs encoding cardiotoxins I, III and N were constructed from the cellular RNA isolated from the venom glands of Naja naja atra by reverse transcription-polymerase chain reaction. A high degree of sequence homology was observed with the three cardiotoxins. The cardiotoxins were subcloned in the expression vector pET 20b(+) and transformed in BL 21(DE3) E. coli strain. The expressed protein was isolated from the inclusion bodies of E. coli and purified by reversed phase high performance liquid chromatography. The purified recombinant cardiotoxin III showed an immunoreactivity with anti-cardiotoxin III antibodies as revealed by immunoblot analysis.