Propionyl coenzyme A is a common intermediate in the 1,2-propanediol and propionate catabolic pathways needed for expression of the prpBCDE operon during growth of Salmonella enterica on 1,2-propanediol.
The studies reported here identify propionyl coenzyme A (propionyl-CoA) as the common intermediate in the 1,2-propanediol and propionate catabolic pathways of Salmonella enterica serovar Typhimurium LT2. Growth on 1,2-propanediol as a carbon and energy source led to the formation and excretion of propionate, whose activation to propionyl-CoA relied on the activities of the propionate kinase (PduW)/phosphotransacetylase (Pta) enzyme system and the CobB sirtuin-controlled acetyl-CoA and propionyl-CoA (Acs, PrpE) synthetases. The different affinities of these systems for propionate ensure sufficient synthesis of propionyl-CoA to support wild-type growth of S. enterica under low or high concentrations of propionate in the environment. These redundant systems of propionyl-CoA synthesis are needed because the prpE gene encoding the propionyl-CoA synthetase enzyme is part of the prpBCDE operon under the control of the PrpR regulatory protein, which needs 2-methylcitrate as a coactivator. Because the synthesis of 2-methylcitrate by PrpC (i.e., the 2-methylcitrate synthase enzyme) requires propionyl-CoA as a substrate, the level of propionyl-CoA needs to be raised by the Acs or PduW-Pta system before 2-methylcitrate can be synthesized and prpBCDE transcription can be activated.
Palacios
Sergio
S
Department of Bacteriology, University of Wisconsin, Madison, Wisconsin 53726-4087, USA.
Starai
Vincent J
VJ
Escalante-Semerena
Jorge C
JC
D000214:Acyl Coenzyme A / Q000378:metabolism*; D003066:Coenzyme A Ligases / Q000378:metabolism; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D009154:Mutation; D009876:Operon; D010709:Phosphate Acetyltransferase / Q000378:metabolism; D017851:Phosphotransferases (Carboxyl Group Acceptor) / Q000378:metabolism; D011422:Propionates / Q000378:metabolism*; D019946:Propylene Glycol / Q000378:metabolism*; D019779:Salmonella enterica / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D037761:Sirtuins / Q000235:genetics
D000214:Acyl Coenzyme A; D029968:Escherichia coli Proteins; D011422:Propionates; C009061:propionyl-coenzyme A; D019946:Propylene Glycol; D010709:Phosphate Acetyltransferase; D017851:Phosphotransferases (Carboxyl Group Acceptor); C111066:TdcD protein, E coli; D037761:Sirtuins; D003066:Coenzyme A Ligases; C068072:propionate - CoA ligase