Wen, Suping, Wilson, David T.R., Kuruppu, Sanjaya, Korsinczky, Michael L.J., Hedrick, Joseph, Pang, Ling, Szeto, Tim, Hodgson, Wayne C., Alewood, Paul F., and Nicholson, Graham M. (2005) Discovery of an MIT-like atracotoxin family: spider venom peptides that share sequence homology but not pharmacological properties with AVIT family proteins. Peptides, 26 (12). pp. 2412-2426.

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Abstract

This project identified a novel family of six 66-68 residue peptides from the venom of two Australian funnel-web spiders, Hadronyche sp. 20 and H. infensa: Orchid Beach (Hexathelidae: Atracinae), that appear to undergo N- and/or C-terminal post-translational modifications and conform to an ancestral protein fold. These peptides all show significant amino acid sequence homology to atracotoxin-Hvf17 (ACTX-Hvf17), a non-toxic peptide isolated from the venom of H. versuta, and a variety of AVIT family proteins including mamba intestinal toxin 1 (MIT1) and its mammalian and piscine orthologs prokineticin 1 (PK1) and prokineticin 2 (PK2). These AVIT family proteins target prokineticin receptors involved in the sensitization of nociceptors and gastrointestinal smooth muscle activation. Given their sequence homology to MIT1, we have named these spider venom peptides the MIT-like atracotoxin (ACTX) family. Using isolated rat stomach fundus or guinea-pig ileum organ bath preparations we have shown that the prototypical ACTX-Hvf17, at concentrations up to 1muM, did not stimulate smooth muscle contractility, nor did it inhibit contractions induced by human PK1 (hPK1). The peptide also lacked activity on other isolated smooth muscle preparations including rat aorta. Furthermore, a FLIPR Ca2+ flux assay using HEK293 cells expressing prokineticin receptors showed that ACTX-Hvf17 fails to activate or block hPK1 or hPK2 receptors. Therefore, while the MIT-like ACTX family appears to adopt the ancestral disulfide-directed beta-hairpin protein fold of MIT1, a motif believed to be shared by other AVIT family peptides, variations in the amino acid sequence and surface charge result in a loss of activity on prokineticin receptors.

Item ID:	39022
Item Type:	Article (Research - C1)
ISSN:	1873-5169
Keywords:	ACTX–Hvf17; mamba intestinal toxin 1; Bv8; prokineticin; funnel-web spider
Funders:	University of Technology, Sydney, Australian Research Council (ARC), Schering-Plough Research Institute
Date Deposited:	25 Jun 2015 03:42
FoR Codes:	03 CHEMICAL SCIENCES > 0304 Medicinal and Biomolecular Chemistry > 030406 Proteins and Peptides @ 100%
SEO Codes:	97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 100%
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