Characterization of two mutant metJ proteins with reduced, temperature-dependent capacity to regulate Escherichia coli K-12 met regulon elements. |
| |
Authors: | G A Bala C D Collier M R Emmett J R Johnson |
| |
Affiliation: | Department of Microbiology, Miami University, Oxford, Ohio 45056. |
| |
Abstract: | At 28 degrees C, but not at 34 or 42 degrees C, strains with the metJ193 allele repressed chromosomal met genes but not a plasmid-borne met promoter. Increasing the metJ193 gene dosage to two copies resulted in overrepression of chromosomal and plasmid-borne met promoters at 28 degrees C. Suppressing the metJ185 amber mutation with supF (tRNATyr) produced the MetJ185F protein. Strains producing MetJ185F repressed chromosomal met promoters but not a plasmid-borne met promoter at 42 degrees C. These are the first known defective MetJ proteins with documented temperature-dependent function. |
| |
Keywords: | |
|
|