4xrd: Difference between revisions
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<StructureSection load='4xrd' size='340' side='right'caption='[[4xrd]], [[Resolution|resolution]] 2.30Å' scene=''> | <StructureSection load='4xrd' size='340' side='right'caption='[[4xrd]], [[Resolution|resolution]] 2.30Å' scene=''> | ||
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>[[4xrd]] is a 5 chain structure with sequence from [ | <table><tr><td colspan='2'>[[4xrd]] is a 5 chain structure with sequence from [https://en.wikipedia.org/wiki/Salmonella_enterica_subsp._enterica_serovar_Typhimurium Salmonella enterica subsp. enterica serovar Typhimurium]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4XRD OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4XRD FirstGlance]. <br> | ||
</td></tr><tr id=' | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.3Å</td></tr> | ||
<tr id=' | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr> | ||
< | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4xrd FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4xrd OCA], [https://pdbe.org/4xrd PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4xrd RCSB], [https://www.ebi.ac.uk/pdbsum/4xrd PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4xrd ProSAT]</span></td></tr> | ||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[ | |||
</table> | </table> | ||
== Function == | == Function == | ||
[ | [https://www.uniprot.org/uniprot/AHPC_SALTY AHPC_SALTY] Directly reduces alkyl hydroperoxides with the use of electrons donated by the 57 kDa flavoprotein alkyl hydroperoxide reductase. | ||
<div style="background-color:#fffaf0;"> | |||
== 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<ref>PMID:28375740</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 4xrd" style="background-color:#fffaf0;"></div> | |||
==See Also== | ==See Also== | ||
*[[Thioredoxin | *[[Thioredoxin reductase 3D structures|Thioredoxin reductase 3D structures]] | ||
== References == | |||
<references/> | |||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
[[Category: Large Structures]] | [[Category: Large Structures]] | ||
[[Category: | [[Category: Salmonella enterica subsp. enterica serovar Typhimurium]] | ||
[[Category: Karplus | [[Category: Karplus PA]] | ||
[[Category: Nelson | [[Category: Nelson K]] | ||
[[Category: Parsonage | [[Category: Parsonage D]] | ||
[[Category: Perkins | [[Category: Perkins A]] | ||
[[Category: Poole | [[Category: Poole L]] | ||
Latest revision as of 10:48, 27 September 2023
Salmonella typhimurium AhpC W169F mutantSalmonella typhimurium AhpC W169F mutant
Structural highlights
FunctionAHPC_SALTY Directly reduces alkyl hydroperoxides with the use of electrons donated by the 57 kDa flavoprotein alkyl hydroperoxide reductase. Publication Abstract from PubMedAIMS: 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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