5uka | pdb_00005uka

Salmonella typhimurium AhpC E49Q mutant

spinqualitylabelsall models 5uka, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5uka is a 5 chain structure with sequence from Salmonella enterica subsp. enterica serovar Typhimurium str. LT2. This structure supersedes the now removed PDB entry 4xs8. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.9Å Ligands: CL, K, NA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function AHPC_SALTY Directly reduces alkyl hydroperoxides with the use of electrons donated by the 57 kDa flavoprotein alkyl hydroperoxide reductase. Publication Abstract from PubMed AIMS: Peroxiredoxins (Prxs) are ubiquitous cysteine-based peroxidases involved in oxidant defense and signal transduction. Despite much study, the precise roles of conserved residues remain poorly defined. In this study, we carried out extensive functional and structural characterization of 10 variants of such residues in a model decameric bacterial Prx. RESULTS: Three active site proximal mutations of Salmonella typhimurium AhpC, T43V, R119A, and E49Q, lowered catalytic efficiency with hydrogen peroxide by 4-5 orders of magnitude, but did not affect reactivity toward their reductant, AhpF. pKa values of the peroxidatic cysteine were also shifted up by 1-1.3 pH units for these and a decamer disruption mutant, T77I. Except for the decamer-stabilizing T77V, all mutations destabilized decamers in the reduced form. In the oxidized form, three mutants-T77V, T43A, and T43S-exhibited stabilized decamers and were more efficiently reduced by AhpF than wild-type AhpC. Crystal structures of most mutants were solved and many showed alterations in stability of the fully folded active site loop. INNOVATION: This is the first study of Prx mutants to comprehensively assess the effects of mutations on catalytic activities, the active site cysteine pKa, and the protein structure and oligomeric status. CONCLUSION: The Arg119 side chain must be properly situated for efficient catalysis, but for other debilitating variants, the functional defects could be explained by structural perturbations and/or associated decamer destabilization rather than direct effects. This underscores the importance of our comprehensive approach. A remarkable new finding was the preference of the reductant for decamers. Antioxid. Redox Signal. 28, 521-536. Experimentally Dissecting the Origins of Peroxiredoxin Catalysis.,Nelson KJ, Perkins A, Van Swearingen AED, Hartman S, Brereton AE, Parsonage D, Salsbury FR Jr, Karplus PA, Poole LB Antioxid Redox Signal. 2018 Mar 1;28(7):521-536. doi: 10.1089/ars.2016.6922. Epub, 2017 Apr 4. PMID:28375740 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Thioredoxin reductase 3D structures

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