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Nucleotide sequence of the guaB locus encoding IMP dehydrogenaseof Escherichia coli K12

1985; Oxford University Press; Volume: 13; Issue: 4 Linguagem: Inglês

10.1093/nar/13.4.1303

1362-4962

A A Tiedeman, John M. Smith,

Amino Acid Enzymes and Metabolism

IMP dehydrogenase, the product of the gua B locus in Escherichia coli K12, catalyzes the synthesis of XMP by the NAD + dependent oxidation of IMP The gua B locus has been subcloned from the Clarke and Carbon plasmid pLC34-10. The sequence of the gua B structural gene and surrounding DNA was determined by the dideoxy chain termination method of Sanger. The 1.533 kb gua B gene encodes an IMP dehydrogenase subunit of molecular weight 54,512. S1 nuclease mapping placed the site of gua BA mRNA initiation approximately 188 bp from the start of the gua B structural gene. The −10 and −35 regions that define the gua BA promoter were located upstream of the start of the gua BA transcription intiation site. The control region of approximately 188 bp does not show any obvious potential for secondary structure. A secondary λ att site has been identified 42 bp distal to the gua B start codon.