Regulation of methionine synthesis in Escherichia coli: Effect of metJ gene product and S-adenosylmethionine on the expression of the metF gene.
The regulation of the expression of the Escherichia coli metF gene, which codes for 5,10-methylenetet-rahydrofolate reductase (EC 1.1.99.15), has been investigated by using a simplified DNA-directed in vitro system that measures the formation of the first dipeptide (fMet-Ser) of the gene product. The synthesis of fMet-Ser directed by a plasmid containing the metF gene is specifically inhibited by metJ protein (repressor protein). S-Adenosylmethionine enhances the inhibition by the metJ protein of metF gene expression. The inhibition by the metJ protein is at the level of transcription and the results suggest that S-adenosylmethionine is functioning as an allosteric effector.
Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110.
R
R
Shoeman
B
B
Redfield
T
T
Coleman
R C
RC
Greene
A A
AA
Smith
N
N
Brot
H
H
Weissbach