@article {Morgado231,
	title = {Redox- and pH-linked conformational changes in triheme cytochrome PpcA from Geobacter sulfurreducens},
	journal = {Biochemical Journal},
	volume = {474},
	number = {2},
	year = {2017},
	note = {n/a},
	pages = {231{\textendash}246},
	publisher = {Portland Press Limited},
	abstract = {<p>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.</p>
},
	issn = {0264-6021},
	doi = {10.1042/BCJ20160932},
	url = {http://www.biochemj.org/content/474/2/231},
	author = {Leonor Morgado and Bruix, Marta and P Raj Pokkuluri and Salgueiro, , Carlos A. and Turner, David L.}
}
