The pyrimidine operon pyrRPB-carA from Lactococcus lactis

Citation
J. Martinussen et al., The pyrimidine operon pyrRPB-carA from Lactococcus lactis, J BACT, 183(9), 2001, pp. 2785-2794
Citations number
42
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
JOURNAL OF BACTERIOLOGY
ISSN journal
0021-9193 → ACNP
Volume
183
Issue
9
Year of publication
2001
Pages
2785 - 2794
Database
ISI
SICI code
0021-9193(200105)183:9<2785:TPOPFL>2.0.ZU;2-F
Abstract
The four genes pyrR, pyrP, pyrB, and carA were found to constitute an opero n in Lactococcus lactis subsp, lactis MG1363. The functions of the differen t genes were established by mutational analysis. The first gene in the oper on is the pyrimidine regulatory gene, pyrR, which is responsible for the re gulation of the expression of the pyrimidine biosynthetic genes leading to UMP formation. The second gene encodes a membrane-bound high-affinity uraci l permease, required for utilization of exogenous uracil. The last two gene s in the operon, pyrB and carA, encode pyrimidine biosynthetic enzymes; asp artate transcarbamoylase (pyrB) is the second enzyme in the pathway, wherea s carbamoyl-phosphate synthetase subunit A (carA) is the small subunit of a heterodimeric enzyme, catalyzing the formation of carbamoyl phosphate. The carA gene product is shown to be required for both pyrimidine and arginine biosynthesis. The expression of the pyrimidine biosynthetic genes includin g the pyrRPB-carA operon is subject to control at the transcriptional level , most probably by an attenuator mechanism in which PyrR acts as the regula tory protein.