Carbon catabolite repression in Bacillus subtilis: quantitative analysis of repression exerted by different carbon sources

Abstract:

In many bacteria glucose is the preferred carbon source and represses the utilization of secondary substrates. In Bacillus subtilis, this carbon catabolite repression (CCR) is achieved by the global transcription regulator CcpA, whose activity is triggered by the availability of its phosphorylated cofactors, HPr(Ser46-P) and Crh(Ser46-P). Phosphorylation of these proteins is catalyzed by the metabolite-controlled kinase HPrK/P. Recent studies have focused on glucose as a repressing substrate. Here, we show that many carbohydrates cause CCR. The substrates form a hierarchy in their ability to exert repression via the CcpA-mediated CCR pathway. Of the two cofactors, HPr is sufficient for complete CCR. In contrast, Crh cannot substitute for HPr on substrates that cause a strong repression. Determination of the phosphorylation state of HPr in vivo revealed a correlation between the strength of repression and the degree of phosphorylation of HPr at Ser46. Sugars transported by the phosphotransferase system (PTS) cause the strongest repression. However, the phosphorylation state of HPr at its His15 residue and PTS transport activity have no impact on the global CCR mechanism, which is a major difference compared to the mechanism operative in Escherichia coli. Our data suggest that the hierarchy in CCR exerted by the different substrates is exclusively determined by the activity of HPrK/P.

SEEK ID: https://fairdomhub.org/publications/61

PubMed ID: 18757537

Projects: BaCell-SysMO

Publication type: Not specified

Journal: J. Bacteriol.

Citation:

Date Published: 29th Aug 2008

Registered Mode: Not specified

Authors: Kalpana D Singh, Matthias H Schmalisch, , Boris Görke

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Created: 20th Aug 2010 at 13:55

Last updated: 8th Dec 2022 at 17:25

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