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Publication Abstract from PubMed

The structure of cytochrome-c (GSU3274) designated as PccH from Geobacter sulfurreducens was determined at 2.0 A resolution. PccH is a small (15 kDa) cytochrome containing one c-type heme, found to be essential for growth of G. sulfurreducens accepting electrons from graphite electrodes poised at -300 mV versus SHE with fumarate as the terminal electron acceptor. The structure of PccH is unique among the monoheme cytochromes described to date. The structural fold of PccH can be described as forming two lobes with the heme sandwiched in a cleft between the two lobes. In addition, PccH has a low reduction potential of -24 mV at pH 7, which is unusual for monoheme cytochromes. Based on difference in structure together with sequence phylogenetic analysis we propose that PccH can be regarded as a first characterized example of a new subclass of class I monoheme cytochromes. The low reduction potential of PccH may enable the protein to be redox active at the typically negative potential ranges encountered by this bacterium. Because PccH is predicted to be located in the periplasm of G. sulfurreducens, it could not be involved in the first step of accepting electrons from the electrode but very likely involved in the downstream electron transport events in the periplasm. This article is protected by copyright. All rights reserved.

The structure of PccH from Geobacter sulfurreducens: A novel low reduction potential monoheme cytochrome essential for accepting electrons from an electrode.,Dantas JM, Campelo LM, Duke NE, Salgueiro CA, Pokkuluri PR FEBS J. 2015 Mar 18. doi: 10.1111/febs.13269. PMID:25786707^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.