Identification of the Bacillus subtilis pur operon repressor.
Transcription of the Bacillus subtilis pur operon is repressed in response to a signal of excess adenine. We have purified the repressor protein and have identified, cloned, and overexpressed the purR regulatory gene that controls transcription initiation of the operon. B. subtilis purR encodes a 62-kDa homodimer that binds to the pur operon control region. The PurR binding site which overlaps the promoter encompasses approximately 110 bp. The protein-DNA interaction is inhibited by 5-phosphoribosyl 1-pyrophosphate. A mutation that deletes the repressor binding site or one that disrupts purR abolishes binding activity in vitro and repression of transcription in vivo in response to the excess adenine signal. These results lead to a model in which an excess-adenine signal is transmitted to PurR via the 5-phosphoribosyl 1-pyrophosphate pool. In addition, purR is autoregulated. There is no structural or mechanistic similarity between the B. subtilis and Escherichia coli purine repressors.
Weng
M
M
Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA.
Nagy
P L
PL
Zalkin
H
H
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D001665:Binding Sites / Q000235:genetics; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005809:Genes, Regulator; D008969:Molecular Sequence Data; D009876:Operon; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C065825:PurR protein, Bacteria; C489317:PurR protein, E coli; D012097:Repressor Proteins