1zmq
From Proteopedia
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Crystal structure of human alpha-defensin-6
Overview
Six alpha-defensins have been found in humans. These small arginine-rich, peptides play important roles in various processes related to host, defense, being the effectors and regulators of innate immunity as well as, enhancers of adoptive immune responses. Four defensins, called neutrophil, peptides 1 through 4, are stored primarily in polymorphonuclear, leukocytes. Major sites of expression of defensins 5 and 6 are Paneth, cells of human small intestine. So far, only one structure of human, alpha-defensin (HNP3) has been reported, and the properties of the, intestine defensins 5 and 6 are particularly poorly understood. In this, report, we present the high-resolution X-ray structures of three human, defensins, 4 through 6, supplemented with studies of their antimicrobial, and chemotactic properties. Despite only modest amino acid sequence, identity, all three defensins share their tertiary structures with other, known alpha- and beta-defensins. Like HNP3 but in contrast to murine or, rabbit alpha-defensins, human defensins 4-6 form characteristic dimers., Whereas antimicrobial and chemotactic activity of HNP4 is somewhat, comparable to that of other human neutrophil defensins, neither of the, intestinal defensins appears to be chemotactic, and for HD6 also an, antimicrobial activity has yet to be observed. The unusual biological, inactivity of HD6 may be associated with its structural properties, somewhat standing out when compared with other human alpha-defensins. The, strongest cationic properties and unique distribution of charged residues, on the molecular surface of HD5 may be associated with its highest, bactericidal activity among human alpha-defensins.
About this Structure
1ZMQ is a Single protein structure of sequence from Homo sapiens with CL as ligand. Full crystallographic information is available from OCA.
Reference
Crystal structures of human alpha-defensins HNP4, HD5, and HD6., Szyk A, Wu Z, Tucker K, Yang D, Lu W, Lubkowski J, Protein Sci. 2006 Dec;15(12):2749-60. Epub 2006 Nov 6. PMID:17088326
Page seeded by OCA on Mon Nov 12 20:37:20 2007
