The small protein CydX is required for function of cytochrome bd oxidase in Brucella abortus.

Yao Hui Sun, Maarten F. de Jong, Andreas B. den Hartigh, Christelle M. Roux, Hortensia G. Rolán, Renée M. Tsolis

Research output: Contribution to journalArticlepeer-review

44 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)47
Number of pages1
JournalFrontiers in cellular and infection microbiology
StatePublished - 2012

ASJC Scopus subject areas

  • Microbiology
  • Microbiology (medical)
  • Infectious Diseases
  • Immunology


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