Metabolic Instability of Escherichia coli Cyclopropane Fatty Acid Synthase Is Due to RpoH-Dependent Proteolysis

AUTOR(ES)

Chang, Ying-Ying

FONTE

American Society for Microbiology

RESUMO

Cyclopropane fatty acids (CFAs) are generally synthesized as bacterial cultures enter stationary phase. In Escherichia coli, the onset of CFA synthesis results from increased transcription of cfa, the gene encoding CFA synthase. However, the increased level of CFA synthase activity is transient; the activity quickly declines to the basal level. We report that the loss of CFA activity is due to proteolytic degradation dependent on expression of the heat shock regulon. CFA synthase degradation is unaffected by mutations in the lon, clpP, and groEL genes or by depletion of the intracellular ATP pools. It seems likely that CFA synthase is the target of an unidentified energy-independent heat shock regulon protease. This seems to be the first example of heat shock-dependent degradation of a normal biosynthetic enzyme.

Documentos Relacionados

• Effect of ppGpp on Escherichia coli Cyclopropane Fatty Acid Synthesis Is Mediated through the RpoS Sigma Factor (ςS)
• Cloning and manipulation of the Escherichia coli cyclopropane fatty acid synthase gene: physiological aspects of enzyme overproduction.
• Properties and biosynthesis of cyclopropane fatty acids in Escherichia coli.
• Regulation of acetohydroxy acid synthase in streptomycin-dependent Escherichia coli.
• Characterization of Escherichia coli mutants completely defective in synthesis of cyclopropane fatty acids.