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Publication Abstract from PubMed

Analysis of the genome of Bacillus halodurans strain C125 indicated that two pathways leading from a cytosine deoxyribonucleotide to dUMP, used for dTMP synthesis, was encoded by the bacterium. The responsible genes, the comEB gene and the dcdB gene, encoding dCMP deaminase and the bifunctional dCTP deaminase:dUTPase (DCD:DUT) were both shown to be expressed in B. halodurans and both genes were subject to repression by the nucleosides, thymidine and deoxycytidine. The latter nucleoside presumably excerts its repression after deamination by cytidine deaminase. Both comEB and dcdB were cloned, overexpressed in E. coli and purified to homogeneity. The enzymes were both active and displayed the expected regulatory properties: activation by dCTP for dCMP deaminase and dTTP inhibition for both enzymes. Structurally, the B. halodurans enzyme resembled Mycobacterium tuberculosis enzyme the most. An investigation of sequenced genomes from other species of the genus Bacillus revealed that not only B. halodurans but also Bacillus pseudofirmus, Bacillus thuringiensis, Bacillus hemocellulosilyticus, Bacillus marmarensis, Bacillus cereus and Bacillus megaterium all encode both the dCMP deaminase and DCD:DUT enzymes. In addition, eight dcdB homologs were registered in entrez-NCBI from Bacillus species within the genus where the whole genome had not yet been sequenced.

Bacillus halodurans strain C125 encodes and synthesizes enzymes from both known pathways to form dUMP directly from cytosine deoxyribonucleotides.,Oehlenschlaeger CB, Lovgreen MN, Reinauer E, Lehtinen E, Pind ML, Harris P, Martinussen J, Willemoes M Appl Environ Microbiol. 2015 Mar 6. pii: AEM.00268-15. PMID:25746996^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.