2ca7

Publication Abstract from PubMed

Conkunitzin-S1 (Conk-S1) is a 60-residue neurotoxin from the venom of the cone snail Conus striatus that interacts with voltage-gated potassium channels. Conk-S1 shares sequence homology with Kunitz-type proteins but contains only two out of the three highly conserved cysteine bridges, which are typically found in these small, basic protein modules. In this study the three-dimensional structure of Conk-S1 has been solved by multidimensional NMR spectroscopy. The solution structure of recombinant Conk-S1 shows that a Kunitz fold is present, even though one of the highly conserved disulfide cross-links is missing. Introduction of a third, homologous disulfide bond into Conk-S1 results in a functional toxin with similar affinity for Shaker potassium channels. The affinity of Conk-S1 can be enhanced by a pore mutation within the Shaker channel pore indicating an interaction of Conk-S1 with the vestibule of potassium channels.

Conkunitzin-S1 is the first member of a new Kunitz-type neurotoxin family. Structural and functional characterization.,Bayrhuber M, Vijayan V, Ferber M, Graf R, Korukottu J, Imperial J, Garrett JE, Olivera BM, Terlau H, Zweckstetter M, Becker S J Biol Chem. 2005 Jun 24;280(25):23766-70. Epub 2005 Apr 15. PMID:15833744^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.