Investigation on the anaerobic propionate degradation by Escherichia coli K12
Simonte, F.M. / Dötsch, A. / Galego, L. / Arraiano, C. / Gescher, J. (2017)
Mol Microbiol., 2017, 103, 1, 55-66, doi: 10.1111/mmi.13541
- Date: Oktober 2016
Propionate is an abundant carboxylic acid in nature. Microorganisms metabolize propionate aerobically via the 2-methylcitrate pathway. This pathway depends on a series of three reactions in the citric acid cycle that leads to the conversion of succinate to oxaloacetate. Interestingly, the γ-proteobacterium Escherichia coli can use propionate as a carbon and electron source under oxic but not under anoxic conditions. RT-PCR and transcriptomic analysis revealed a posttranscriptional regulation of the prpBCDE-gene cluster encoding the necessary enzymes for propionate metabolism. The polycistronic mRNA seems to be hydrolyzed in the 3'-5' direction under anoxic conditions. This regulatory strategy is highly constructive because the last gene of the operon encodes the first enzyme of the propionate metabolism. Further analysis revealed that RNase R is involved in the hydrolysis of the prp transcripts. Consequently, an rnr-deletion strain could metabolize propionate under anoxic conditions. To the best of our knowledge, this is the first study describing the influence of RNase R on the anaerobic metabolism of E. coli.