Involvement of SenC in assembly of cytochrome c oxidase in Rhodobacter capsulatus.
SenC, a Sco1 homolog found in the purple photosynthetic bacteria, has been implicated in affecting photosynthesis and respiratory gene expression, as well as assembly of cytochrome c oxidase. In this study, we show that SenC from Rhodobacter capsulatus is involved in the assembly of a fully functional cbb(3)-type cytochrome c oxidase, as revealed by decreased cytochrome c oxidase activity in a senC mutant. We also show that a putative copper-binding site in SenC is required for activity and that a SenC deletion phenotype can be rescued by the addition of exogenous copper to the growth medium. In addition, we demonstrate that a SenC mutation has an indirect effect on gene expression caused by a reduction in cytochrome c oxidase activity. A model is proposed whereby a reduction in cytochrome c oxidase activity impedes the flow of electrons through the respiratory pathway, thereby affecting the oxidation/reduction state of the ubiquinone pool, leading to alterations of photosystem and respiratory gene expression.
Swem
Danielle L
DL
Department of Biology, Indiana University, Bloomington, 47405, USA.
Swem
Lee R
LR
Setterdahl
Aaron
A
Bauer
Carl E
CE
D020816:Amino Acid Motifs / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003300:Copper / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000096:biosynthesis* / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D010084:Oxidation-Reduction; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D016354:Rhodobacter capsulatus / Q000201:enzymology* / Q000378:metabolism; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; C096879:SenC protein, Rhodobacter capsulatus; D003300:Copper; D003576:Electron Transport Complex IV