2yyf

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Revision as of 11:19, 9 April 2008

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Template:STRUCTURE 2yyf

Purification and structural characterization of a D-amino acid containing conopeptide, marmophine, from Conus marmoreus

Overview

Cone snails, a group of gastropod animals that inhabit tropical seas, are capable of producing a mixture of peptide neurotoxins, namely conotoxins, for defense and predation. Conotoxins are mainly disulfide-rich short peptides that act on different ion channels, neurotransmitter receptors, or transporters in the nervous system. They exhibit highly diverse compositions, structures, and biological functions. In this work, a novel Cys-free 15-residue conopeptide from Conus marmoreus was purified and designated as conomarphin. Conomarphin is unique because of its d-configuration Phe at the third residue from the C-terminus, which was identified using HPLC by comparing native conomarphin fragments and the corresponding synthetic peptides cleaved by different proteases. Surprisingly, the cDNA-encoded precursor of conomarphin was found to share the conserved signal peptide with other M-superfamily conotoxins, clearly indicating that conomarphin should belong to the M-superfamily, although conomarphin shares no homology with other six-Cys-containing M-superfamily conotoxins. Furthermore, NMR spectroscopy experiments established that conomarphin adopts a well-defined structure in solution, with a tight loop in the middle of the peptide and a short 3(10)-helix at the C-terminus. By contrast, no loop in l-Phe13-conomarphin was found, which suggests that d-Phe13 is essential for the structure of conomarphin. In conclusion, conomarphin may represent a new conotoxin family, whose biological activity remains to be identified.

About this Structure

2YYF is a Single protein structure. Full crystallographic information is available from OCA.

Reference

Purification and structural characterization of a d-amino acid-containing conopeptide, conomarphin, from Conus marmoreus., Han Y, Huang F, Jiang H, Liu L, Wang Q, Wang Y, Shao X, Chi C, Du W, Wang C, FEBS J. 2008 Mar 18;. PMID:18355315