1pe4
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(New page: 200px<br /><applet load="1pe4" size="450" color="white" frame="true" align="right" spinBox="true" caption="1pe4" /> '''SOLUTION STRUCTURE OF TOXIN CN12 FROM CENTRU...)
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Revision as of 21:36, 20 November 2007
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SOLUTION STRUCTURE OF TOXIN CN12 FROM CENTRUROIDES NOXIUS ALFA SCORPION TOXIN ACTING ON SODIUM CHANNELS. NMR STRUCTURE
Overview
Cn12 isolated from the venom of the scorpion Centruroides noxius has 67, amino-acid residues, closely packed with four disulfide bridges. Its, primary structure and disulfide bridges were determined. Cn12 is not, lethal to mammals and arthropods in vivo at doses up to 100 microg per, animal. Its 3D structure was determined by proton NMR using 850 distance, constraints, 36 phi angles derived from 36 coupling constants obtained by, two different methods, and 22 hydrogen bonds. The overall structure has a, two and half turn alpha-helix (residues 24-32), three strands of, antiparallel beta-sheet (residues 2-4, 37-40 and 45-48), and a type II, turn (residues 41-44). The amino-acid sequence of Cn12 resembles the beta, scorpion toxin class, although patch-clamp experiments showed the, induction of supplementary slow inactivation of Na(+) channels in F-11, cells (mouse neuroblastoma N18TG-2 x rat DRG2), which means that it, behaves more like an alpha scorpion toxin. This behaviour prompted us to, analyse Na(+) channel binding sites using information from 112 Na(+), channel gene clones available in the literature, focusing on the, extracytoplasmic loops of the S5-S6 transmembrane segments of domain I and, the S3-S4 segments of domain IV, sites considered to be responsible for, binding alpha scorpion toxins.
About this Structure
1PE4 is a Single protein structure of sequence from Centruroides noxius. Full crystallographic information is available from OCA.
Reference
NMR solution structure of Cn12, a novel peptide from the Mexican scorpion Centruroides noxius with a typical beta-toxin sequence but with alpha-like physiological activity., del Rio-Portilla F, Hernandez-Marin E, Pimienta G, Coronas FV, Zamudio FZ, Rodriguez de la Vega RC, Wanke E, Possani LD, Eur J Biochem. 2004 Jun;271(12):2504-16. PMID:15182366
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