The rph-pyrE operon in E. coli contains two genes. one of which is involved in the production of uridine monophosphate, and the other is non-active due to a frameshift mutation. There are no known activators or repressors of the operon. The first gene, rph, encodes the truncated inactive ribonuclease PH, which is inactivated due to a frameshift mutation in the E. coli strain K12 MG1665, a popular lab strain of the bacteria. This mutation allows the protein to be transcribed and translated, but it is non-functional. If restored to its functional state, the protein is involved in tRNA and rRNA degradation. The second gene, pyrE, encodes orotate phosphoribosyltransferase, an enzyme catalyzes the formation of orotidine 5'-phosphate and diphosphate from orotate and 5-phospho-alpha-D-ribose 1-diphosphate. This is one step of the pathway of the biosynthesis of UMP, an RNA nucleotide.

Operon: Ribonuclease & Pyrimidine Biosynthesis References