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Feedback control of ribosome function in Escherichia coli
1Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, TX 75083-0688, USA. bremer3@attglobal.net
Biochimie
|November 15, 2007
Summary
E. coli ribosome function is regulated by a feedback loop involving the spoT gene and ppGpp. This mechanism ensures optimal peptide chain elongation rates by adjusting ribosome synthesis and amino acid consumption.
Area of Science:
- Molecular Biology
- Microbiology
- Systems Biology
Background:
- Ribosome function, measured by peptide chain elongation rate, is crucial for bacterial growth.
- A previously proposed feedback mechanism involves guanosine tetraphosphate (ppGpp) and the spoT gene in E. coli.
Purpose of the Study:
- To provide detailed evidence for the proposed feedback loop regulating ribosome function.
- To conduct a mathematical analysis of the feedback mechanism's dynamics.
Main Methods:
- Detailed description and evidence supporting the feedback loop.
- Mathematical modeling and analysis of SpoT ppGpp synthetase activity.
Main Results:
- The feedback loop involves ppGpp generation via SpoT activation when elongation rates are submaximal.
- Accumulation of ppGpp downregulates ribosome synthesis, increasing amino acid availability for remaining ribosomes.
- Mathematical analysis predicts maximal SpoT activity at half-maximal ribosome function rates.
Conclusions:
- The study elaborates on a feedback loop controlling E. coli ribosome function.
- The findings support the hypothesis that SpoT activity is optimized at half-maximal translation rates, irrespective of the precise regulatory mechanism.
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