Effects of limited aeration and of the ArcAB system on intermediary pyruvate catabolism in Escherichia coli.
The capacity of Escherichia coli to adapt its catabolism to prevailing redox conditions resides mainly in three catabolic branch points involving (i) pyruvate formate-lyase (PFL) and the pyruvate dehydrogenase complex (PDHc), (ii) the exclusively fermentative enzymes and those of the Krebs cycle, and (iii) the alternative terminal cytochrome bd and cytochrome bo oxidases. A quantitative analysis of the relative catabolic fluxes through these pathways is presented for steady-state glucose-limited chemostat cultures with controlled oxygen availability ranging from full aerobiosis to complete anaerobiosis. Remarkably, PFL contributed significantly to the catabolic flux under microaerobic conditions and was found to be active simultaneously with PDHc and cytochrome bd oxidase-dependent respiration. The synthesis of PFL and cytochrome bd oxidase was found to be maximal in the lower microaerobic range but not in a delta ArcA mutant, and we conclude that the Arc system is more active with respect to regulation of these two positively regulated operons during microaerobiosis than during anaerobiosis.
Alexeeva
S
S
EC Slater Institute, University of Amsterdam, 1018 WS Amsterdam, The Netherlands.
de Kort
B
B
Sawers
G
G
Hellingwerf
K J
KJ
de Mattos
M J
MJ
D000123:Acetyltransferases / Q000378:metabolism; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D003573:Cytochrome b Group; D003580:Cytochromes / Q000378:metabolism; D045222:Electron Transport Chain Complex Proteins; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005947:Glucose / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D019289:Pyruvic Acid / Q000378:metabolism*; D012097:Repressor Proteins
D001425:Bacterial Outer Membrane Proteins; D003573:Cytochrome b Group; D003580:Cytochromes; D045222:Electron Transport Chain Complex Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D012097:Repressor Proteins; C041610:arcA protein, E coli; D009243:NAD; D019289:Pyruvic Acid; D010088:Oxidoreductases; C040077:cytochrome bd terminal oxidase complex, E coli; D000123:Acetyltransferases; C022560:formate C-acetyltransferase; D011494:Protein Kinases; C065271:arcB protein, E coli; D005947:Glucose; D010100:Oxygen