Overproduction of CcmABCDEFGH restores cytochrome c maturation in a DsbD deletion strain of E. coli: another route for reductant?
The multidomain transmembrane protein DsbD is essential for cytochrome c maturation (Ccm) in Escherichia coli and transports reductant to the otherwise oxidising environment of the bacterial periplasm. The Ccm proteins ABCDEFGH are also essential and we show that the overproduction of these proteins can unexpectedly complement for the absence of DsbD in a deletion strain by partially restoring the production of an exogenous c-type cytochrome under aerobic and anaerobic conditions. This suggests that one or more of the Ccm proteins can provide reductant to the periplasm. The Ccm proteins do not, however, restore the normal disulfide mis-isomerisation phenotype of the deletion strain, as shown by assay of the multidisulfide-bonded enzyme urokinase.
Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
Julie M
JM
Stevens
Euan H
EH
Gordon
Stuart J
SJ
Ferguson
D000332:Aerobiosis; D000693:Anaerobiosis; D045304:Cytochromes c / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000096:biosynthesis*; D017353:Gene Deletion; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D019704:Protein Disulfide-Isomerases / Q000235:genetics*; D014568:Urokinase-Type Plasminogen Activator / Q000032:analysis / Q000378:metabolism
D029968:Escherichia coli Proteins; D045304:Cytochromes c; D014568:Urokinase-Type Plasminogen Activator; D019704:Protein Disulfide-Isomerases