2eem

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Solution structure of the synthetic mytilin

Overview

Mytilin is a 34-residue antibacterial peptide from the mussel Mytilus, galloprovincialis, which in addition possesses in vitro antiviral, activity. The three-dimensional solution structure of the synthetic, mytilin was established by using 1H NMR and consists of the common, cysteine-stabilized alphabeta motif close to the one observed in the, mussel defensin MGD-1. Mytilin is characterized by 8 cysteines engaged in, four disulfide bonds (2-27, 6-29, 10-31, and 15-34) only involving the, beta-strand II. Hydrophilic and hydrophobic areas of mytilin account for, 63% and 37%, respectively, a ratio very close to that of MGD-1 (64% and, 36%). One linear and three cyclic fragments were designed from the, interstrand loop sequence known to retain the biological activities in, MGD-1. Only the fragment of 10 amino acids (C10C) constrained by two, disulfide bonds in a stable beta-hairpin structure was able to inhibit the, mortality of Palaemon serratus shrimp injected with white spot syndrome, virus (WSSV). Fifty percent inhibition was obtained by in vitro, pre-incubation of WSSV with 45muM of C10C compared with 7muM for mytilin., Interaction between the fragment and the virus occurred very rapidly as, 40% survival was recorded after only 1min of pre-incubation. In addition, C10C was capable of inhibiting in vitro growth of Vibrio splendidus LGP32, (MIC 125muM), Vibrio anguillarum (MIC 2mM), Micrococcus lysodeikticus and, Escherichia coli (MIC 1mM). Destroying the cysteine-stabilized alphabeta, structure or shortening the C1OC fragment to the C6C fragment with only, one disulfide bond resulted in loss of both antiviral and antibacterial, activities. Increasing the positive net charge did not enforce the, antibacterial activity and completely suppressed the antiviral one. The, C10C-designed peptide from mytilin appeared comparable in composition and, structure with protegrin, tachyplesin and polyphemusin.

About this Structure

2EEM is a Single protein structure of sequence from [1]. Full crystallographic information is available from OCA.

Reference

NMR structure of mussel mytilin, and antiviral-antibacterial activities of derived synthetic peptides., Roch P, Yang Y, Toubiana M, Aumelas A, Dev Comp Immunol. 2007 Jun 26;. PMID:17628674

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