2ux1
Identification of two zinc-binding sites in the Streptococcus suis Dpr protein
Structural highlights
FunctionDPS_STRSU Protects DNA from oxidative damage by sequestering intracellular Fe(2+) ion and storing it in the form of Fe(3+) oxyhydroxide mineral. One hydrogen peroxide oxidizes two Fe(2+) ions, which prevents hydroxyl radical production by the Fenton reaction (By similarity). It binds and incorporates Fe(2+) iron. Is responsible for hydrogen peroxide resistance. Does not bind DNA. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedStreptococcus suis Dpr is an iron-binding protein involved in oxidative stress resistance. It belongs to the bacterial Dps protein family whose members form dodecameric assemblies. Previous studies have shown that zinc and terbium inhibit iron incorporation in Listeria innocua Dps protein. In order to gain structural insights into the inhibitory effect of zinc and terbium, the crystal structures of Streptococcus suis Dpr complexes with these ions were determined at 1.8 A and 2.1 A, respectively. Both ions were found to bind at the ferroxidase center and in the same location as iron. In addition, a novel zinc-binding site formed by His40 and His44 was identified. Both His residues were found to be present within all known Streptococcus suis Dpr variants and in Streptococcus pneumoniae, Streptococcus gordonii, and Streptococcus sanguinis Dpr proteins. Amino acid sequence alignment of Dpr with other Dps family members revealed that His44 is highly conserved, in contrast to His40. The inhibitory effect of zinc and terbium on iron oxidation in Dpr was studied in vitro, and it was found that both ions at concentrations >0.2 mM almost completely abolish iron binding. These results provide a structural basis for the inhibitory effect of zinc and terbium in the Dps family of proteins, and suggest a potential role of the Dps proteins in zinc detoxification mechanisms involving the second zinc-binding site. Structural basis of the zinc- and terbium-mediated inhibition of ferroxidase activity in Dps ferritin-like proteins.,Havukainen H, Haataja S, Kauko A, Pulliainen AT, Salminen A, Haikarainen T, Finne J, Papageorgiou AC Protein Sci. 2008 Sep;17(9):1513-21. Epub 2008 Jun 13. PMID:18552126[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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