Participation of the Entner-Doudoroff pathway in Escherichia coli strains with an inactive phosphotransferase system (PTS- Glc+) in gluconate and glucose batch cultures.
The activity of the enzymes of the central metabolic pathways has been the subject of intensive analysis; however, the Entner-Doudoroff (ED) pathway has only recently begun to attract attention. The metabolic response to edd gene knockout in Escherichia coli JM101 and PTS- Glc+ was investigated in gluconate and glucose batch cultures and compared with other pyruvate kinase and PTS mutants previously constructed. Even though the specific growth rates between the strain carrying the edd gene knockout and its parent JM101 and PTS- Glc+ edd and its parent PTS- Glc+ were very similar, reproducible changes in the specific consumption rates and biomass yields were obtained when grown on glucose. These results support the participation of the ED pathway not only on gluconate metabolism but on other metabolic and biochemical processes in E. coli. Despite that gluconate is a non-PTS carbohydrate, the PTS- Glc+ and derived strains showed important reductions in the specific growth and gluconate consumption rates. Moreover, the overall activity of the ED pathway on gluconate resulted in important increments in PTS- Glc+ and PTS- Glc+ pykF mutants. Additional results obtained with the pykA pykF mutant indicate the important contribution of the pyruvate kinase enzymes to pyruvate synthesis and energy production in both carbon sources.
Ponce
Elizabeth
E
Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Dept. Of Marine Biotechnology, Km 107 Carretera Tijuana-Ensenada, C.P. 22860 Ensenada, B.C., Mexico. eponce@cicese.mx
García
Mauricio
M
Muñoz
Maria Enriqueta
ME
D000446:Aldehyde-Lyases / Q000032:analysis; D018533:Biomass; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism*; D017353:Gene Deletion; D005942:Gluconates / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006836:Hydro-Lyases / Q000032:analysis / Q000235:genetics; D010770:Phosphotransferases / Q000235:genetics; D011770:Pyruvate Kinase / Q000235:genetics
D005942:Gluconates; D010770:Phosphotransferases; D011770:Pyruvate Kinase; D000446:Aldehyde-Lyases; C100131:phospho-2-keto-3-deoxy-gluconate aldolase; D006836:Hydro-Lyases; C022362:phosphogluconate dehydratase; D005947:Glucose; C030691:gluconic acid