tailieunhanh - Báo cáo Y học: The solution structure of gomesin, an antimicrobial cysteine-rich peptide from the spider

Gomesin is the first peptide isolated from spider exhibiting antimicrobial activities. This highly cationic peptide is composed of 18 amino-acid residues including four cysteines forming two disulfide linkages. The solution structure of gomesin has been determined using proton two-dimensional NMR (2D-NMR) and restrained molecular dynamics calculations. The global fold of gomesin consists in a wellresolved two-stranded antiparallel b sheet connected by a noncanonical b turn. | Eur. J. Biochem. 269 1190-1198 2002 FEBS 2002 The solution structure of gomesin an antimicrobial cysteine-rich peptide from the spider Nicolas Mandard1 Philippe Bulet2 Anita Caille1 Sirlei Daffre3 and Francoise Vovelle1 1 Centre de Biophysique Moleculaire CNRS Orleans France 2Institut de Biologie Moleculaire et Cellulaire CNRS Strasbourg France 3Departamento de Parasitologia ICB Universidade de Sao Paulo Brazil Gomesin is the first peptide isolated from spider exhibiting antimicrobial activities. This highly cationic peptide is composed of 18 amino-acid residues including four cysteines forming two disulfide linkages. The solution structure of gomesin has been determined using proton two-dimensional NMR 2D-NMR and restrained molecular dynamics calculations. The global fold of gomesin consists in a well-resolved two-stranded antiparallel b sheet connected by a noncanonical b turn. A comparison between the structures of gomesin and protegrin-1 from porcine and androctonin from scorpion outlines several common features in the distribution of hydrophobic and hydrophilic residues. The N- and C-termini the b turn and one face of the b sheet are hydrophilic but the hydrophobicity of the other face depends on the peptide. The similarities suggest that the molecules interact with membranes in an analogous manner. The importance of the intramolecular disulfide bridges in the biological activity of gomesin is being investigated. Keywords spider cysteine-rich antimicrobial peptide b sheet NMR. In recent years it has become widely recognized that animal defense systems rely on inducible or constitutive expression of antimicrobial peptides in response to bacterial and or fungal infections. Among these antimicrobial molecules open-ended cyclic cysteine-rich peptides are the most widespread. They have been characterized in plants invertebrates and vertebrates. Structurally they can be classified into a peptides adopting a b sheet structure namely the mammalian defensins 1 b .