CLONING AND SEQUENCE-ANALYSIS OF NOVEL CARDIOTOXINS CLBP FROM VENOM GLANDS OF NAJA-NAJA ATRA/

Seventeen cardiotoxins (CTXs)(3) and four CLBPs(3) have been identifie d by screening cDNA library and in conjunction with the PCR approach. Among the 17 CTXs, two have silent substitutions, five have previously been identified by traditional protein sequencing methods. In additio n, ten not well known CTX genes and one new CLBP have been identified. These CTX genes show very high sequence homology with the major varia tions occurring at the tip of each individual loop. Although the CTX i soforms differ by only one or few residues and this subtle differences strongly influences the structure and function of the CTX isoforms. W e have identified a novel CTX-3c sequence which represents a blend of the CTX-1 and CTX-3 sequence. Based on the sequence comparison with ot her CTX isoforms from the same snake source, we predict interesting fu nctional properties for CTX-3c.