@article {10.1042/BCJ20210365,
	title = {Rational design of electron/proton transfer mechanisms in the exoelectrogenic bacteria Geobacter sulfurreducens},
	journal = {Biochemical Journal},
	volume = {478},
	number = {14},
	year = {2021},
	note = {<p>n/a</p>
},
	month = {07},
	pages = {2871-2887},
	abstract = {<p>{The redox potential values of cytochromes can be modulated by the protonation/deprotonation of neighbor groups (redox-Bohr effect), a mechanism that permits the proteins to couple electron/proton transfer. In the respiratory chains, this effect is particularly relevant if observed in the physiological pH range, as it may contribute to the electrochemical gradient for ATP synthesis. A constitutively produced family of five triheme cytochromes (PpcA-E) from the bacterium Geobacter sulfurreducens plays a crucial role in extracellular electron transfer, a hallmark that permits this bacterium to be explored for several biotechnological applications. Two members of this family (PpcA and PpcD) couple electron/proton transfer in the physiological pH range, a feature not shared with PpcB and PpcE. That ability is crucial for G. sulfurreducens{\textquoteright} growth in Fe(III)-reducing habitats since extra contributors to the electrochemical gradient are needed. It was postulated that the redox-Bohr effect is determined by the nature of residue 6, a leucine in PpcA/PpcD and a phenylalanine in PpcB/PpcE. To confirm this hypothesis, Phe6 was replaced by leucine in PpcB and PpcE. The functional properties of these mutants were investigated by NMR and UV{\textendash}visible spectroscopy to assess their capability to couple electron/proton transfer in the physiological pH range. The results obtained showed that the mutants have an increased redox-Bohr effect and are now capable of coupling electron/proton transfer. This confirms the determinant role of the nature of residue 6 in the modulation of the redox-Bohr effect in this family of cytochromes, opening routes to engineer Geobacter cells with improved biomass production.}</p>
},
	issn = {0264-6021},
	doi = {10.1042/BCJ20210365},
	url = {https://doi.org/10.1042/BCJ20210365},
	author = {Silva, , Marta A. and Portela, Pilar C. and Salgueiro, , Carlos A.}
}
