Open AccessCo‐regulation of lipoamide dehydrogenase and 2‐oxoglutarate dehydrogenase synthesis in Escherichia coli : characterisation of an ArcA binding site in the lpd promoter
Author(s) -
Cunningham Louise,
Georgellis Dimitris,
Green Jeffrey,
Guest John R.
Publication year - 1998
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1998.tb13347.x
Subject(s) - operon , promoter , pyruvate dehydrogenase complex , microbiology and biotechnology , biology , dehydrogenase , transcription (linguistics) , escherichia coli , biochemistry , chemistry , gene , enzyme , gene expression , linguistics , philosophy
The lipoamide dehydrogenase gene ( lpdA ) encoding the E3 subunits of both the pyruvate dehydrogenase and 2‐oxoglutarate dehydrogenase complexes of Escherichia coli , is expressed from the upstream pdh and internal lpd promoters of the pdh operon ( pdhR‐aceEF‐lpdA ). Under aerobic conditions, the specific components of the 2‐oxoglutarate dehydrogenase complex encoded by the sucAB genes in the sdhCDAB‐sucABCD operon are expressed from the sdh promoter. The provision of lipoamide dehydrogenase subunits for assembly into the 2‐oxoglutarate dehydrogenase complex could thus be controlled by co‐regulation of the lpd promoter with the sdh promoter. Here, the transcription start point of the lpd promoter was defined by primer extension analysis, and an ArcA binding site, TGTTAA CA AT , overlapping the lpd promoter and matching the consensus at 8 out of 10 positions, was identified by in vitro footprint analysis. PdhR was not bound to the lpd promoter nor was ArcA bound specifically to the pdh promoter. These results support the view that co‐regulation of the lpd and sdh promoters is mediated primarily by ArcA.