1fd4
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HUMAN BETA-DEFENSIN 2
OverviewOverview
Defensins are small cationic peptides that are crucial components of, innate immunity, serving as both antimicrobial agents and chemoattractant, molecules. The specific mechanism of antimicrobial activity involves, permeabilization of bacterial membranes. It has been postulated that, individual monomers oligomerize to form a pore through anionic membranes, although the evidence is only indirect. Here, we report two high, resolution x-ray structures of human beta-defensin-2 (hBD2). The phases, were experimentally determined by the multiwavelength anomalous, diffraction method, utilizing a novel, rapid method of derivatization with, halide ions. Although the shape and charge distribution of the monomer are, similar to those of other defensins, an additional alpha-helical region, makes this protein topologically distinct from the mammalian alpha- and, beta-defensin structures reported previously. hBD2 forms dimers, topologically distinct from that of human neutrophil peptide-3. The, quaternary octameric arrangement of hBD2 is conserved in two crystal, forms. These structures provide the first detailed description of, dimerization of beta-defensins, and we postulate that the mode of, dimerization of hBD2 is representative of other beta-defensins. The, structural and electrostatic properties of the hBD2 octamer support an, electrostatic charge-based mechanism of membrane permeabilization by, beta-defensins, rather than a mechanism based on formation of, bilayer-spanning pores.
DiseaseDisease
Known diseases associated with this structure: Crohn disease, susceptibility to OMIM:[602215]
About this StructureAbout this Structure
1FD4 is a Single protein structure of sequence from [1] with SO4 as ligand. Full crystallographic information is available from OCA.
ReferenceReference
The structure of human beta-defensin-2 shows evidence of higher order oligomerization., Hoover DM, Rajashankar KR, Blumenthal R, Puri A, Oppenheim JJ, Chertov O, Lubkowski J, J Biol Chem. 2000 Oct 20;275(42):32911-8. PMID:10906336
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