The cvpA-purF-ubiX operon in E. coli contains three genes that encode various proteins. The operon can be inhibited by the PurR transcriptional repressor, which binds to the promoter region and represses transcription. Hypoxanthine can also bind to PurR, which induces a conformational change in the protein, allowing it to bind more strongly to DNA, and increasing its repressive properties. The first gene in the operon, cvpA, encodes the colicin V producrtion protein, which is required for colicin V to be produced via a plasmid. Colicins are toxins produced by bacteria that can be used to kill other bacterial strains than the one releasing them. The second gene, purF, encodes amidophosphoribosyltransferase, a protein that forms a homotetramer along with magnesium as a cofactor, and catalyzes the formation of phosphoribosylamine from glutamine or ammonia and phosphoribosylpyrophosphate. Phosphoribosylamine is then used to form inosinic acid, which can then be used to form AMP and GMP. The final gene, ubiX, encodes 3-octaprenyl-4-hydroxybenzoate carboxy-lyase, a protein that catalyzes the synthesis of prenyl-FMNH2 and a phosphate group from FMNH2 and dimethylallyl phosphate. It can also work with the UbiD protein in the biosynthesis of coenzyme Q.

Operon: De Novo Purine Nucleotide Biosynthesis References