Protein phosphorylation and global regulation in escherichia coli = 대장균에서의 단백질 인산화와 global regulation

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Acetyl phosphate is known to phosphorylate several regulatory proteins of Escherichia coli and therefore was proposed as a global regulator. A number of proteins in crude extract were observed to be phosphorylated by acetyl phosphate in vitro, and six of them were characterized here. A sequencing of N-terminal amino acids revealed that they are phosphopentomutase, succinyl-CoA synthetase, phosphoglycerate mutase, nucleoside diphosphate kinase, and an unknown protein. Also included was CheY, a response regulator protein identified by immunoblotting. The chemical properties of the phosphoryl groups of the proteins indicated that acetyl phosphate may use the same residues, His or Asp, previously characterized as phosphorylation sites. Phosphorylation of the enzymes with acetyl phosphate followed slower kinetics than that of CheY, taking more than 5 min to reach their steady state levels of phosphorylation. The role of acetyl phosphate in vivo was investigated by devising a method for in vivo phosphorylation using minicells. Labeling with inorganic [$^32P$]phosphate revealed that the phosphorylation levels of succinyl-CoA synthetase, phosphoglycerate mutase and CheY in minicells were higher in ackA mutant than in pta ackA double mutant, supporting in vivo phosphorylation by acetyl phosphate. These observations made on the enzymes which are implicated in the metabolic shift between biosynthesis and degradation led us to propose that acetyl phosphate serves as a metabolic modulator affecting the growth rate of cells. The role of acetyl phosphate in the reaction catalyzed by succinyl- CoA synthetase was investigated. The phosphorylation of succinyl-CoA synthetase alpha-subunit by acetyl phosphate requires the presence of magnesium. Chemical properties of the phosphoryl group and peptide mapping indicate that the phosphorylation site by acetyl phosphate would probably be the active site histidine residue. The enzyme utilizes acetyl phosphate and ADP to produce ATP, wh...
Park, Chan-Kyuresearcher박찬규researcher
한국과학기술원 : 생물과학과,
Issue Date
108907/325007 / 000905812

학위논문(박사) - 한국과학기술원 : 생물과학과, 1996.8, [ 126 p. ]


Phosphotransferase system; Succinyl-CoA synthetase; Acetyl phosphate; Escherichia coli; Phosphotransferase system; Succinyl-CoA synthetase; Acetyl phosphate; Protein phosphorylation; 단백질 인산화; 대장균

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