title: Functional characterization of PccH, a key cytochrome for electron transfer from electrodes to the bacterium Geobacter sulfurreducens.
abstract: The cytochrome PccH from Geobacter sulfurreducens (Gs) plays a crucial role in current-consuming fumarate-reducing biofilms. Deletion of pccH gene inhibited completely electron transfer from electrodes toward Gs cells. The pccH gene was cloned and the protein heterologously expressed in Escherichia coli. Complementary biophysical techniques including CD, UV-visible and NMR spectroscopy were used to characterize PccH. This cytochrome contains one low-spin c-type heme with His-Met axial coordination and unusual low-reduction potential. This reduction potential is pH-dependent, within the Gs physiological pH range, and is discussed within the context of the electron transfer mechanisms from electrodes to Gs cells.
authors.affiliation: Requimte-CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus Caparica, 2829-516 Caparica, Portugal.
authors.forename: Joana M
authors.initials: JM
authors.lastname: Dantas
authors.forename: Diogo M
authors.initials: DM
authors.lastname: Tomaz
authors.forename: Leonor
authors.initials: L
authors.lastname: Morgado
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Salgueiro
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D018441:Biofilms; D003001:Cloning, Molecular; D003580:Cytochromes / Q000737:chemistry*; D004247:DNA / Q000737:chemistry; D004566:Electrodes; D004579:Electron Transport; D015964:Gene Expression Regulation, Bacterial; D045302:Geobacter / Q000235:genetics / Q000378:metabolism*; D006418:Heme / Q000737:chemistry; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D003580:Cytochromes; D006418:Heme; D004247:DNA
keywords: Electron transfer; Geobacter; Geobacter sulfurreducens cytochrome encoded by gene GSU3274; Heme protein; PccH; c-Type cytochrome