Regulation of methionine synthesis in Escherichia coli: effect of metJ gene product and S-adenosylmethionine on the in vitro expression of the metB, metL and metJ genes.
The regulation of the expression of three Escherichia coli met genes, metB, which codes for cystathionine gamma-synthetase (EC 4.2.99.9), metL, which codes for aspartokinase II-homoserine dehydrogenase II (EC 2.7.2.4-EC 1.1.1.3) and metJ, which codes for the methionine regulon aporepressor, has been studied using highly purified DNA-directed in vitro protein synthesis systems. In a system where the entire gene product is synthesized, the expression of the metB and metL genes is specifically inhibited by MetJ protein (repressor protein) and S-adenosylmethionine (AdoMet). In a simplified system that measures the formation of the first dipeptide of the gene product (fMet-Ala for the metJ gene), MetJ protein and AdoMet partially repress (approximately 40-60%) metJ gene expression. Thus, the metJ gene can be partially autoregulated by its gene product.
D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D005796:Genes; D005798:Genes, Bacterial; D008715:Methionine / Q000096:biosynthesis / Q000235:genetics*; D010957:Plasmids; D012097:Repressor Proteins / Q000502:physiology*; D012436:S-Adenosylmethionine / Q000494:pharmacology*; D013698:Templates, Genetic; D014157:Transcription Factors / Q000502:physiology*
D001426:Bacterial Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D012436:S-Adenosylmethionine; D008715:Methionine