A biochemical approach to study the role of the terminal oxidases in aerobic respiration in Shewanella oneidensis MR-1.
The genome of the facultative anaerobic γ-proteobacterium Shewanella oneidensis MR-1 encodes for three terminal oxidases: a bd-type quinol oxidase and two heme-copper oxidases, a A-type cytochrome c oxidase and a cbb 3-type oxidase. In this study, we used a biochemical approach and directly measured oxidase activities coupled to mass-spectrometry analysis to investigate the physiological role of the three terminal oxidases under aerobic and microaerobic conditions. Our data revealed that the cbb 3-type oxidase is the major terminal oxidase under aerobic conditions while both cbb 3-type and bd-type oxidases are involved in respiration at low-O2 tensions. On the contrary, the low O2-affinity A-type cytochrome c oxidase was not detected in our experimental conditions even under aerobic conditions and would therefore not be required for aerobic respiration in S. oneidensis MR-1. In addition, the deduced amino acid sequence suggests that the A-type cytochrome c oxidase is a ccaa 3-type oxidase since an uncommon extra-C terminal domain contains two c-type heme binding motifs. The particularity of the aerobic respiratory pathway and the physiological implication of the presence of a ccaa 3-type oxidase in S. oneidensis MR-1 are discussed.
CNRS, Aix-Marseille Université, Laboratoire de Bioénergétique et Ingénierie des Protéines, UMR 7281, IMM, Marseille, France.
Sébastien
S
Le Laz
CNRS, Aix-Marseille Université, Laboratoire de Bioénergétique et Ingénierie des Protéines, UMR 7281, IMM, Marseille, France.
Arlette
A
Kpebe
CNRS, Aix-Marseille Université, Unité de fermentation, FR3479, IMM, Marseille, France.
Marielle
M
Bauzan
CNRS, Aix-Marseille Université, Plate-forme Protéomique, FR3479, IMM, MaP IBiSA, Marseille, France.
Sabrina
S
Lignon
CNRS, Aix-Marseille Université, Laboratoire de Bioénergétique et Ingénierie des Protéines, UMR 7281, IMM, Marseille, France.
Marc
M
Rousset
CNRS, Aix-Marseille Université, Laboratoire de Bioénergétique et Ingénierie des Protéines, UMR 7281, IMM, Marseille, France.
Myriam
M
Brugna
D000332:Aerobiosis; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D019069:Cell Respiration / Q000235:genetics; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D017353:Gene Deletion; D023061:Gene Order; D005810:Multigene Family; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010089:Oxidoreductases, N-Demethylating / Q000235:genetics / Q000378:metabolism; D020592:Shewanella / Q000235:genetics / Q000378:metabolism*
D010088:Oxidoreductases; C024748:copper oxidase; D010089:Oxidoreductases, N-Demethylating; C022726:tetramethylphenylenediamine oxidase; C414443:cbb3 oxidase; D003576:Electron Transport Complex IV