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The Role of the Pro Sequence of Bacillus subtilisςK in Controlling Activity in Transcription Initiation
The sigma (ς) subunit of prokaryotic RNA polymerase is required for specific recognition of promoter DNA sequences and transcription initiation. Regulation of gene expression can therefore be achieved by modulating the activity of the ς subunit. In Bacillus subtilis the mother cell-specific sporulat...
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Published in: | The Journal of biological chemistry 1997-12, Vol.272 (49), p.31029-31035 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The sigma (ς) subunit of prokaryotic RNA polymerase is required for specific recognition of promoter DNA sequences and transcription initiation. Regulation of gene expression can therefore be achieved by modulating the activity of the ς subunit. In Bacillus subtilis the mother cell-specific sporulation sigma factor, ςK, is synthesized as a precursor protein, pro-ςK, with a 20-amino acid pro sequence. This pro sequence renders ςK inactive for directing transcription of ςK-dependent genesin vivo until the pro sequence is proteolytically removed. To understand the role of the pro sequence in controlling ςK activity, we have constructed NH2-terminal truncations of pro-ςK and characterized their behaviorin vitro at the gerE promoter. In this report we show that the pro sequence inactivates ςK by interfering with the ability of ςK to associate with the core subunits of polymerase and also influences the interactions between holoenzyme and promoter DNA. Additionally, removal of as few as 6 amino acids (pro-ςKΔ6) is sufficient to activate pro-ςK for DNA binding and transcription initiation. Surprisingly, pro-ςKΔ6 binds to DNA with higher affinity and stimulates transcription 30-fold more efficiently than ςK, under certain conditions. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.272.49.31029 |