Molecular isoforms of cobra venom factor-like proteins in the venom of Austrelaps superbus

Abstract

During our search for novel proteins, we isolated a polypeptide, AVFi?!c, from the venom of the snake Austrelaps superbus. Functional studies on recombinant AVFi?!c conclude that it lacks potent chemotactic activity. Complete cDNA sequences and putative promoter fragments of the isoforms of AVF-1 (AVFi?!c precursor) and its isoform AVF-2 (expressed in venom gland) and their paralogs (C3-1 and C3-2 expressed in liver) have been determined. cDNA sequence analysis of these four genes suggests that these genes might have evolved by recent gene duplication events. Two variants of AVF-1 (AVF-1a and AVF-1b) identified in the venom showed the ability to deplete complement in human and guinea pig serum. Observations made in this study bring about a potential role for AVF as a suitable candidate for therapeutic use; understand structure-function relationship of C3 related proteins and as a guide for better design of a??humanizeda?? CVF for therapeutic use.