2bkc

THE X-RAY STRUCTURE OF THE H43G LISTERIA INNOCUA DPS MUTANT

spinqualitylabelsall models 2bkc, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2bkc is a 24 chain structure with sequence from Listeria innocua. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 1qgh, 2bjy, 2bk6 Resources: FirstGlance, OCA, RCSB, PDBsum 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 PubMed The role of the ferroxidase center in iron uptake and hydrogen peroxide detoxification was investigated in Listeria innocua Dps by substituting the iron ligands His31, His43, and Asp58 with glycine or alanine residues either individually or in combination. The X-ray crystal structures of the variants reveal only small alterations in the ferroxidase center region compared to the native protein. Quenching of the protein fluorescence was exploited to assess stoichiometry and affinity of metal binding. Substitution of either His31 or His43 decreases Fe(II) affinity significantly with respect to wt L. innocua Dps (K approximately 10(5) vs approximately 10(7) M(-)(1)) but does not alter the binding stoichiometry [12 Fe(II)/dodecamer]. In the H31G-H43G and H31G-H43G-D58A variants, binding of Fe(II) does not take place with measurable affinity. Oxidation of protein-bound Fe(II) increases the binding stoichiometry to 24 Fe(III)/dodecamer. However, the extent of fluorescence quenching upon Fe(III) binding decreases, and the end point near 24 Fe(III)/dodecamer becomes less distinct with increase in the number of mutated residues. In the presence of dioxygen, the mutations have little or no effect on the kinetics of iron uptake and in the formation of micelles inside the protein shell. In contrast, in the presence of hydrogen peroxide, with increase in the number of substitutions the rate of iron oxidation and the capacity to inhibit Fenton chemistry, thereby protecting DNA from oxidative damage, appear increasingly compromised, a further indication of the role of ferroxidation in conferring peroxide tolerance to the bacterium. The unusual intersubunit ferroxidase center of Listeria innocua Dps is required for hydrogen peroxide detoxification but not for iron uptake. A study with site-specific mutants.,Ilari A, Latella MC, Ceci P, Ribacchi F, Su M, Giangiacomo L, Stefanini S, Chasteen ND, Chiancone E Biochemistry. 2005 Apr 19;44(15):5579-87. PMID:15823016 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ferritin

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