The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
Gene Review

carB  -  carbamoyl-phosphate synthase large subunit

Escherichia coli str. K-12 substr. MG1655

Synonyms: ECK0034, JW0031, cap, pyrA
Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

Disease relevance of carB

  • The carAB operon from E. coli hybridized with the gonococcal clones that carried carA or carB genes under conditions of high stringency, detecting 80% or greater similarity and showing that the nucleotide sequence of the carbamoylphosphate synthetase genes is very similar in these two organisms [1].
  • The first committed reaction in pyrimidine biosynthesis in Escherichia coli and Salmonella typhimurium is catalyzed by the allosteric enzyme aspartate transcarbamoylase (aspartate carbamoyltransferase; carbamoylphosphate:L-aspartate carbamoyltransferase, EC, the product of the pyrB-pyrI operon [2].

High impact information on carB

  • Analysis of the sequence coding for carbamoyl-phosphate synthetase I indicates that the gene has arisen from a fusion of two ancestral genes: one homologous to Escherichia coli carA, coding for a glutaminase subunit, and the second homologous to the carB gene that codes for the synthetase subunit [3].
  • We have determined the nucleotide sequence of a 4-kilobase-pair cloned fragment of E. coli DNA with genetic determinants for carB [4].
  • Previous genetic and biochemical studies indicate that the carB gene of Escherichia coli codes for the large subunit of carbamoyl-phosphate synthetase (EC [4].
  • Synthesis of aspartate transcarbamoylase in Escherichia coli: transcriptional regulation of the pyrB-pyrI operon [2].
  • The plasmid, pHN12, carries a functional carB gene [5].

Biological context of carB

  • We found that DIF-1 did not affect the expression of the tagB or carB genes, both of which are prestalk specific and essential for PST-A cell differentiation [6].
  • Whereas carA and carB are separated by a short noncoding intercistronic region, the homologous sequences of the CAD gene encode an amino acid bridge [7].
  • Transposon Tn5 mutagenesis was used to localize the carA and carB genes on the cloned R. meliloti DNA [8].
  • The sequence revealed the presence of two open reading frames, pyrR and pyrP, located immediately upstream of the previously sequenced pyrB gene encoding the pyrimidine biosynthesis enzyme aspartate transcarbamoylase [9].


  1. Cloning and organization of seven arginine biosynthesis genes from Neisseria gonorrhoeae. Picard, F.J., Dillon, J.R. J. Bacteriol. (1989) [Pubmed]
  2. Synthesis of aspartate transcarbamoylase in Escherichia coli: transcriptional regulation of the pyrB-pyrI operon. Navre, M., Schachman, H.K. Proc. Natl. Acad. Sci. U.S.A. (1983) [Pubmed]
  3. The gene coding for carbamoyl-phosphate synthetase I was formed by fusion of an ancestral glutaminase gene and a synthetase gene. Nyunoya, H., Broglie, K.E., Lusty, C.J. Proc. Natl. Acad. Sci. U.S.A. (1985) [Pubmed]
  4. The carB gene of Escherichia coli: a duplicated gene coding for the large subunit of carbamoyl-phosphate synthetase. Nyunoya, H., Lusty, C.J. Proc. Natl. Acad. Sci. U.S.A. (1983) [Pubmed]
  5. In vivo synthesis of carbamyl phosphate from NH3 by the large subunit of Escherichia coli carbamyl phosphate synthetase. Rubino, S.D., Nyunoya, H., Lusty, C.J. J. Biol. Chem. (1987) [Pubmed]
  6. Initial cell type divergence in Dictyostelium is independent of DIF-1. Shaulsky, G., Loomis, W.F. Dev. Biol. (1996) [Pubmed]
  7. Evidence that mammalian glutamine-dependent carbamyl phosphate synthetase arose through gene fusion. Kern, C.B., Lusty, C.J., Davidson, J.N. J. Mol. Evol. (1992) [Pubmed]
  8. Genetic analysis of carbamoylphosphate synthesis in Rhizobium meliloti 104A14. Kerppola, T.K., Kahn, M.L. J. Gen. Microbiol. (1988) [Pubmed]
  9. The pyrimidine biosynthesis operon of the thermophile Bacillus caldolyticus includes genes for uracil phosphoribosyltransferase and uracil permease. Ghim, S.Y., Neuhard, J. J. Bacteriol. (1994) [Pubmed]
WikiGenes - Universities