Functional analysis of the Escherichia coli K-12 cyn operon transcriptional regulation.
The cynTSX operon enables Escherichia coli K-12 to degrade and use cyanate as a sole nitrogen source. The promoter of this operon is positively regulated by cyanate and the CynR protein. CynR, a member of the LysR family of regulatory proteins, binds specifically to a 136-bp DNA fragment containing both the cynR and the cynTSX promoters. In this study, we report the results of DNase I digestion studies showing that CynR protects a 60-bp region on the cynR coding strand and a 56-bp sequence on the cynTSX coding strand. CynR binding was not affected by cyanate or its structural homolog azide, a gratuitous inducer of the operon. However, CynR-induced bending of two different DNA fragments was detected. The amount of bending was decreased by cyanate.
Department of Biochemistry, University of Minnesota, St. Paul 55108.
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Lamblin
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JA
Fuchs
D001386:Azides / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D019759:Carbon-Nitrogen Lyases; D002256:Carbonic Anhydrases / Q000235:genetics; D003485:Cyanates / Q000378:metabolism*; D004268:DNA-Binding Proteins; D004790:Enzyme Induction; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D008190:Lyases / Q000235:genetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009876:Operon / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D015534:Trans-Activators; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D001386:Azides; D001426:Bacterial Proteins; D003485:Cyanates; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C074784:cynR protein, E coli; D008190:Lyases; D002256:Carbonic Anhydrases; C019953:cyanate hydrolase; D019759:Carbon-Nitrogen Lyases