The Escherichia coli CydX protein is a member of the CydAB cytochrome bd oxidase complex and is required for cytochrome bd oxidase activity.
VanOrsdel CE, Bhatt S, Allen RJ, Brenner EP, Hobson JJ, Jamil A, Haynes BM, Genson AM, Hemm MR. The Escherichia coli CydX protein is a member of the CydAB cytochrome bd oxidase complex and is required for cytochrome bd oxidase activity. J Bacteriol. 2013 Aug; 195(16):3640-50.