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Hydramacin-1: Structure and antibacterial activity of a peptide from the basal metazoan Hydra
Structural highlights
FunctionHYDMA_HYDVU Cationic antimicrobial peptide potently active against Gram-positive and Gram-negative bacteria including multi-resistant human pathogenic strains. Is not active against the Gram-positive Coccus species, Gram-negative non-fermentation species and against the fungus C.albicans. It leads to aggregation of bacteria as an initial step of its bactericidal mechanism. Aggregated cells are connected via electron-dense contacts and adopt a thorn apple-like morphology. Hydramycin contains a belt of positively charged residues that separate two hydrophobic areas. This structure may explain the observed aggregation of bacteria, since each of these areas can immerse into the outer leaflets of the membranes of two individual bacteria. Is able to permeabilize membranes of viable bacteria at low and neutral pH values, but no pore-forming activity is not detected.[1] [2] Publication Abstract from PubMedHydramacin-1 is a novel antimicrobial protein recently discovered during investigations of the epithelial defense of the ancient metazoan Hydra. The amino acid sequence of hydramacin-1 shows no sequence homology to any known antimicrobial proteins. Determination of the solution structure revealed that hydramacin-1 possesses a disulfide bridge-stabilized alphabeta motif. This motif is the common scaffold of the knottin protein fold. The structurally closest relatives are the scorpion oxin-like superfamily. Within this superfamily hydramacin-1 establishes a new family of proteins that all share antimicrobial activity. Hydramacin-1 is potently active against Gram-positive and Gram-negative bacteria including multi-resistant human pathogenic strains. It leads to aggregation of bacteria as an initial step of its bactericidal mechanism. Aggregated cells are connected via electron-dense contacts and adopt a thorn apple-like morphology. Analysis of the hydramacin-1 structure revealed an unusual distribution of amino acid side chains on the surface. A belt of positively charged residues is sandwiched by two hydrophobic areas. Based on this characteristic surface feature and on biophysical analysis of protein-membrane interactions, we propose a model that describes the aggregation effect exhibited by hydramacin-1. Hydramacin-1, structure and antibacterial activity of a protein from the basal metazoan Hydra.,Jung S, Dingley AJ, Augustin R, Anton-Erxleben F, Stanisak M, Gelhaus C, Gutsmann T, Hammer MU, Podschun R, Bonvin AM, Leippe M, Bosch TC, Grotzinger J J Biol Chem. 2009 Jan 16;284(3):1896-905. Epub 2008 Nov 19. PMID:19019828[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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