Specific recognition of the Bacillus subtilis gnt cis-acting catabolite-responsive element by a protein complex formed between CcpA and seryl-phosphorylated HPr.
Catabolite repression of various Bacillus subtilis catabolic operons which carry a cis-acting catabolite-responsive element (CRE), such as the gnt operon, is mediated by CcpA, a protein belonging to the GalR-Lacl family of bacterial transcriptional repressors/activators, and the seryl-phosphorylated form of HPr, a phosphocarrier protein of the phosphoenolpyruvate:sugar phosphotransferase system. Footprinting experiments revealed that the purified CcpA protein interacted with P-ser-HPr to cause specific protection of the gnt CRE against DNase I digestion. The specific recognition of the gnt CRE was confirmed by the results of footprinting experiments using mutant gnt CREs carrying one of the following base substitutions within the CRE consensus sequence: G to T at position +149 or C to T at position +154 (+1 is the gnt transcription initiation nucleotide). The two mutant CREs causing a partial relief from catabolite repression were not protected by the CcpA/P-ser-HPr complex in footprinting experiments. Based on these and previous findings, we propose a molecular mechanism underlying catabolite repression in B. subtilis mediated by CcpA and P-ser-HPr.
Fujita
Y
Y
Department of Biotechnology, Faculty of Engineering, Fukuyama University, Hiroshima, Japan.
Miwa
Y
Y
Galinier
A
A
Deutscher
J
J
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D015342:DNA Probes; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D009876:Operon; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000378:metabolism*; D010766:Phosphorylation; D010768:Phosphoserine; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D015183:Restriction Mapping
D001426:Bacterial Proteins; D015342:DNA Probes; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D011994:Recombinant Proteins; D012097:Repressor Proteins; C069286:catabolite control proteins, bacteria; D010768:Phosphoserine; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C030182:phosphocarrier protein HPr