Autoregulation of PurR repressor synthesis and involvement of purR in the regulation of purB, purC, purL, purMN and guaBA expression in Escherichia coli.
The purR gene encodes a repressor (PurR) controlling the synthesis of the enzymes of purine biosynthesis. The subunit of PurR was identified as a 38-kDa polypeptide by SDS/polyacrylamide gel electrophoresis. Analysis of a purR-lacZ transcriptional fusion indicated that purR expression is autoregulated. This was confirmed by gel retardation and DNaseI footprinting experiments, where two PurR-binding sites were identified in the transcribed part of purR. Introduction of a purR mutation in wild-type and pur-lac fusion strains was found to abolish purine repression of all genes of the purine biosynthetic pathway except for purA.
Institute of Biological Chemistry B, University of Copenhangen, Denmark.
L M
LM
Meng
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M
Kilstrup
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P
Nygaard
D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D009875:Operator Regions, Genetic; D010957:Plasmids; D011687:Purines / Q000378:metabolism*; D012097:Repressor Proteins / Q000032:analysis / Q000096:biosynthesis* / Q000502:physiology; D014157:Transcription Factors / Q000096:biosynthesis*
D011687:Purines; D012097:Repressor Proteins; D014157:Transcription Factors; D004247:DNA