The capsule biosynthesis, or CPS operon, is a section of the genome present in some Escherichia coli, of which regulates the production of polysaccharides making up the bacterial capsule.
[1] These polysaccharides help protect the bacteria from harsh environments, toxic chemicals, and bacteriophages.
The CPS operon contains genes which code for the following proteins: The CPS operon is likely transcriptionally regulated by the Rcs (regulation of capsule synthesis) proteins.
[1] Reduced levels of membrane-derived oligosaccharides result in autophosphorylation of RcsC.
The same operon is present in Klebsiella species, possibly as a result of horizontal gene transfer.