Genes and evolution of two-domain toxins from lynx spider venom

Spiderines are comparatively long polypeptide toxins (similar to 110 residues) from lynx spiders (genus Oxyopes). They are built of an N-terminal linear cationic domain (similar to 40 residues) and a C-terminal knottin domain (similar to 60 residues). The linear domain empowers spiderines with strong cytolytic activity. In the present work we report 16 novel spiderine sequences from Oxyopes takobius and Oxyopes lineatus classified into two subfamilies. Strikingly, negative selection acts on both linear and knottin domains. Genes encoding Oxyopes two-domain toxins were sequenced and found to be intronless. We further discuss a possible scenario of lynx spider modular toxin evolution. (c) 2014 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.