Molecule of the Month
October 2005

CSTX-13 is a component of the venom of the spider Cupiennius salei, which enhances the neurotoxic activity of the main venom component CSTX-1. In contrast to CSTX-1, CSTX-13 is a two-chain peptide with two interchain and two intrachain disulphide bridges, consisting of 78 amino acids. Amino acid sequence and disulphide-bridge pattern have been elucidated in our laboratories.

This work was carried out in the group of Prof. Johann Schaller.


  • B. Wullschleger, L. Kuhn-Nentwig, J. Tromp, U. Kämpfer, J. Schaller, S. Schürch, W. Nentwig;
    "CSTX-13, a highly synergistically acting two-chain neurotoxic enhancer in the venom of the spider Cupiennius salei (Ctenidae)"
    Proc. Natl. Acad. Sci. USA, 101, 11251-11256, (2004); doi:10.1073/pnas.0402226101.