View source for 6u97


==Structure of OmcF_H47I mutant==
<StructureSection load='6u97' size='340' side='right'caption='[[6u97]], [[Resolution|resolution]] 1.13&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6u97]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Geobacter_sulfurreducens_PCA Geobacter sulfurreducens PCA]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6U97 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6U97 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.13&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</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=6u97 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6u97 OCA], [https://pdbe.org/6u97 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6u97 RCSB], [https://www.ebi.ac.uk/pdbsum/6u97 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6u97 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q74AE4_GEOSL Q74AE4_GEOSL] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The monoheme outer membrane cytochrome F (OmcF) from Geobacter sulfurreducens plays an important role in Fe(III) reduction and electric current production. The electrochemical characterization of this cytochrome has shown that its redox potential is modulated by the solution pH (redox-Bohr effect) endowing the protein with the necessary properties to couple electron and proton transfer in the physiological range. The analysis of the OmcF structures in the reduced and oxidized states showed that with the exception of the side chain of histidine 47 (His(47)), all other residues with protonatable side chains are distant from the heme iron and, therefore, are unlikely to affect the redox potential of the protein. The protonatable site at the imidazole ring of His(47) is in the close proximity to the heme and, therefore, this residue was suggested as the redox-Bohr center. In the present work, we tested this hypothesis by replacing the His(47) with non-protonatable residues (isoleucine - OmcFH47I and phenylalanine - OmcFH47F). The structure of the mutant OmcFH47I was determined by X-ray crystallography to 1.13 A resolution and showed only minimal changes at the site of the mutation. Both mutants were (15)N-labeled and their overall folding was confirmed to be the same as the wild-type by NMR spectroscopy. The pH dependence of the redox potential of the mutants was measured by cyclic voltammetry. Compared to the wild-type protein, the magnitude of the redox-Bohr effect in the mutants was smaller, but not fully abolished, confirming the role of His(47) on the pH modulation of OmcF's redox potential. However, the pH effect on the heme substituents' NMR chemical shifts suggested that the heme propionate P13 also contributes to the overall redox-Bohr effect in OmcF. In physiological terms, the contribution of two independent acid-base centers to the observed redox-Bohr effect confers OmcF a higher versatility to environmental changes by coupling electron/proton transfer within a wider pH range.

Modulation of the Redox Potential and Electron/Proton Transfer Mechanisms in the Outer Membrane Cytochrome OmcF From Geobacter sulfurreducens.,Teixeira LR, Cordas CM, Fonseca MP, Duke NEC, Pokkuluri PR, Salgueiro CA Front Microbiol. 2020 Jan 14;10:2941. doi: 10.3389/fmicb.2019.02941. eCollection , 2019. PMID:32010071<ref>PMID:32010071</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6u97" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Geobacter sulfurreducens PCA]]
[[Category: Large Structures]]
[[Category: Pokkuluri PR]]