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Characterization of the molecular mechanisms involved in the differential production of erythrose‐4‐phosphate dehydrogenase, 3‐phosphoglycerate kinase and class II fructose‐1,6‐bisphosphate aldolase in Escherichia coli
Author(s) -
Bardey Vincent,
Vallet Corinne,
Robas Nathalie,
Charpentier Bruno,
Thouvenot Benoit,
Mougin Annie,
Hajnsdorf Eliane,
Régnier Philippe,
Springer Mathias,
Branlant Christiane
Publication year - 2005
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2005.04762.x
Subject(s) - biology , phosphoglycerate kinase , rnase p , aldolase a , open reading frame , fructose bisphosphate aldolase , phosphofructokinase 2 , dehydrogenase , biochemistry , microbiology and biotechnology , gene , rna , peptide sequence , enzyme
Summary A gapA‐pgk gene tandem coding the glyceraldehyde 3‐phosphate dehydrogenase and 3‐phosphoglycerate kinase, is most frequently found in bacteria. However, in Enterobacteriaceae , gapA is replaced by an epd open reading frame (ORF) coding an erythrose‐4‐phosphate dehydrogenase and an fbaA ORF coding the class II fructose‐1,6‐bisphosphate aldolase follows pgk . Although epd expression is very low in Escherichia coli , we show that, in the presence of glucose, the 3 epd , pgk and fbaA ORFs are efficiently cotranscribed from promoter epd P0. Conservation of promoter epd P0 is likely due to its important role in modulation of the metabolic flux during glycolysis and gluconeogenesis. As a consequence, we found that the epd translation initiation region and ORF have been adapted in order to limit epd translation and to create an efficient RNase E entry site. We also show that fbaA is cotranscribed with pgk , from promoter epd P0 or an internal pgk P1 promoter of the extended ‐10 class. The differential expression of pgk and fbaA also depends upon an RNase E segmentation process, leading to individual mRNAs with different stabilities. The secondary structures of the RNA regions containing the RNase E sites were experimentally determined which brings important information on the structural features of RNase E ectopic sites.