<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Leonor Morgado</style></author><author><style face="normal" font="default" size="100%">Bruix, Marta</style></author><author><style face="normal" font="default" size="100%">P Raj Pokkuluri</style></author><author><style face="normal" font="default" size="100%">Salgueiro, , Carlos A.</style></author><author><style face="normal" font="default" size="100%">Turner, David L.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Redox- and pH-linked conformational changes in triheme cytochrome PpcA from Geobacter sulfurreducens</style></title><secondary-title><style face="normal" font="default" size="100%">Biochemical Journal</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2017</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.biochemj.org/content/474/2/231</style></url></web-urls></urls><number><style face="normal" font="default" size="100%">2</style></number><publisher><style face="normal" font="default" size="100%">Portland Press Limited</style></publisher><volume><style face="normal" font="default" size="100%">474</style></volume><pages><style face="normal" font="default" size="100%">231–246</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Accepted Manuscript online November 14, 2016.The periplasmic triheme cytochrome PpcA from Geobacter sulfurreducens is highly abundant; it is the likely reservoir of electrons to the outer surface to assist the reduction of extracellular terminal acceptors; these include insoluble metal oxides in natural habitats and electrode surfaces from which electricity can be harvested. A detailed thermodynamic characterization of PpcA showed that it has an important redox-Bohr effect that might implicate the protein in e-/H+ coupling mechanisms to sustain cellular growth. This functional mechanism requires control of both the redox state and the protonation state. In the present study, isotope-labeled PpcA was produced and the three-dimensional structure of PpcA in the oxidized form was determined by NMR. This is the first solution structure of a G. sulfurreducens cytochrome in the oxidized state. The comparison of oxidized and reduced structures revealed that the heme I axial ligand geometry changed and there were other significant changes in the segments near heme I. The pH-linked conformational rearrangements observed in the vicinity of the redox-Bohr center, both in the oxidized and reduced structures, constitute the structural basis for the differences observed in the pKa values of the redox-Bohr center, providing insights into the e-/H+ coupling molecular mechanisms driven by PpcA in G. sulfurreducens.EET, extracellular electron transfer; IM, inner membrane; IPTG, isopropyl β-d-thiogalactoside; MFCs, microbial fuel cells; NOE, Nuclear Overhauser effect; OM, outer membrane; rmsd, root mean square deviation.&lt;/p&gt;
</style></abstract><notes><style face="normal" font="default" size="100%">n/a</style></notes></record></records></xml>