The small protein CydX is required for function of cytochrome bd oxidase in Brucella abortus.
A large number of hypothetical genes potentially encoding small proteins of unknown function are annotated in the Brucella abortus genome. Individual deletion of 30 of these genes identified four mutants, in BAB1_0355, BAB2_0726, BAB2_0470, and BAB2_0450 that were highly attenuated for infection. BAB2_0726, an YbgT-family protein located at the 3' end of the cydAB genes encoding cytochrome bd ubiquinal oxidase, was designated cydX. A B. abortus cydX mutant lacked cytochrome bd oxidase activity, as shown by increased sensitivity to H(2)O(2), decreased acid tolerance and increased resistance to killing by respiratory inhibitors. The C terminus, but not the N terminus, of CydX was located in the periplasm, suggesting that CydX is an integral cytoplasmic membrane protein. Phenotypic analysis of the cydX mutant, therefore, suggested that CydX is required for full function of cytochrome bd oxidase, possibly via regulation of its assembly or activity.
Department of Medical Microbiology and Immunology, University of California at Davis, Davis CA, USA.
Yao-Hui
YH
Sun
Maarten F
MF
de Jong
Andreas B
AB
den Hartigh
Christelle M
CM
Roux
Hortensia G
HG
Rolán
Renée M
RM
Tsolis
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002003:Brucella abortus / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D002006:Brucellosis / Q000382:microbiology / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D017353:Gene Deletion; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D014774:Virulence
D001426:Bacterial Proteins; D008565:Membrane Proteins; D010088:Oxidoreductases; C432586:ubiquinol oxidase