Investigation on the anaerobic propionate degradation by Escherichia coli K12.
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.
Department of Applied Biology, Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
Francesca M
FM
Simonte
Department of Microbiology on Natural and Technical Interfaces, Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany.
Andreas
A
Dötsch
Instituto de Tecnologia Química e Biológica (ITQB), Universidade Nova de Lisboa, Oeiras, Portugal.
Lisete
L
Galego
Instituto de Tecnologia Química e Biológica (ITQB), Universidade Nova de Lisboa, Oeiras, Portugal.
Cecilia
C
Arraiano
Department of Applied Biology, Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.|Institute for Biological Interfaces, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany.
Johannes
J
Gescher
D000693:Anaerobiosis / Q000502:physiology; D002951:Citrates / Q000378:metabolism; D002952:Citric Acid Cycle / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D048168:Escherichia coli K12 / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D005095:Exoribonucleases / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D005810:Multigene Family / Q000235:genetics; D009876:Operon / Q000235:genetics; D011422:Propionates / Q000378:metabolism*
D002951:Citrates; D029968:Escherichia coli Proteins; D011422:Propionates; C489683:rnr protein, E coli; C031605:2-methylcitric acid; D005095:Exoribonucleases