title: Identification of a multi-protein reductive dehalogenase complex in Dehalococcoides mccartyi strain CBDB1 suggests a protein-dependent respiratory electron transport chain obviating quinone involvement.
abstract: Dehalococcoides mccartyi strain CBDB1 is an obligate organohalide-respiring bacterium using only hydrogen as electron donor and halogenated organics as electron acceptor. Here, we studied proteins involved in the respiratory chain under non-denaturing conditions. Using blue native gel electrophoresis (BN-PAGE), gel filtration and ultrafiltration an active dehalogenating protein complex with a molecular mass of 250-270 kDa was identified. The active subunit of reductive dehalogenase (RdhA) colocalised with a complex iron-sulfur molybdoenzyme (CISM) subunit (CbdbA195) and an iron-sulfur cluster containing subunit (CbdbA131) of the hydrogen uptake hydrogenase (Hup). No colocalisation between the catalytically active subunits of hydrogenase and reductive dehalogenase was found. By two-dimensional BN/SDS-PAGE the stability of the complex towards detergents was assessed, demonstrating stepwise disintegration with increasing detergent concentrations. Chemical cross-linking confirmed the presence of a higher molecular mass reductive dehalogenase protein complex composed of RdhA, CISM I and Hup hydrogenase and proved to be a potential tool for stabilising protein-protein interactions of the dehalogenating complex prior to membrane solubilisation. Taken together, the identification of the respiratory dehalogenase protein complex and the absence of indications for quinone participation in the respiration suggest a quinone-independent protein-based respiratory electron transfer chain in D. mccartyi.
authors.affiliation: Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318, Leipzig, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Kublik
authors.affiliation: Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318, Leipzig, Germany.
authors.forename: Darja
authors.initials: D
authors.lastname: Deobald
authors.affiliation: Institute of Microbiology, Martin-Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Hartwig
authors.affiliation: Department of Proteomics, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318, Leipzig, Germany.
authors.forename: Christian L
authors.initials: CL
authors.lastname: Schiffmann
authors.affiliation: Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318, Leipzig, Germany.
authors.forename: Adarelys
authors.initials: A
authors.lastname: Andrades
authors.affiliation: Department of Proteomics, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318, Leipzig, Germany.|Department of Metabolomics, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318, Leipzig, Germany.|Centre for Microbial Communities, University of Aalborg, Fredrik Bajers Vej 7H, 9220, Aalborg East, Denmark.
authors.forename: Martin
authors.initials: M
authors.lastname: von Bergen
authors.affiliation: Institute of Microbiology, Martin-Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle, Germany.
authors.forename: R Gary
authors.initials: RG
authors.lastname: Sawers
authors.affiliation: Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318, Leipzig, Germany. lorenz.adrian@ufz.de.
authors.forename: Lorenz
authors.identifier: 0000-0001-8205-0842
authors.initials: L
authors.lastname: Adrian
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D016227:Benzoquinones / Q000378:metabolism*; D041862:Chloroflexi / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism; D004579:Electron Transport; D054879:Halogenation; D006864:Hydrogenase / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D016227:Benzoquinones; C004532:quinone; D006864:Hydrogenase