Structure determination of human and murine beta-defensins reveals structural conservation in the absence of significant sequence similarity.Bauer, F., Schweimer, K., Kluver, E., Conejo-Garcia, J.R., Forssmann, W.G., Rosch, P., Adermann, K., Sticht, H.
(2001) Protein Sci. 10: 2470-2479
- PubMed: 11714914
- DOI: 10.1110/ps.24401
- Primary Citation of Related Structures:
- PubMed Abstract:
Defensins are cationic and cysteine-rich peptides that play a crucial role in the host defense against microorganisms of many organisms by their capability to permeabilize bacterial membranes. The low sequence similarity among the members of the larg ...
Defensins are cationic and cysteine-rich peptides that play a crucial role in the host defense against microorganisms of many organisms by their capability to permeabilize bacterial membranes. The low sequence similarity among the members of the large mammalian beta-defensin family suggests that their antimicrobial activity is largely independent of their primary structure. To investigate to what extent these defensins share a similar fold, the structures of the two human beta-defensins, hBD-1 and hBD-2, as well as those of two novel murine defensins, termed mBD-7 and mBD-8, were determined by nuclear magnetic resonance spectroscopy. All four defensins investigated share a striking similarity on the level of secondary and tertiary structure including the lack of a distinct hydrophobic core, suggesting that the fold is mainly stabilized by the presence of three disulfide bonds. In addition to the overall shape of the molecules, the ratio of solvent-exposed polar and hydrophobic side chains is also very similar among the four defensins investigated. It is significant that beta-defensins do not exhibit a common pattern of charged and hydrophobic residues on the protein surface and that the beta-defensin-specific fold appears to accommodate a wide range of different amino acids at most sequence positions. In addition to the implications for the mode of biological defensin actions, these findings are of particular interest because beta-defensins have been suggested as lead compounds for the development of novel peptide antibiotics for the therapy of infectious diseases.
Lehrstuhl für Biopolymere, Universität Bayreuth, D-95440 Bayreuth, Germany.