1887

Abstract

Summary: Cells of K12 were sensitive to 100 m-methylammonium when cultured under nitrogen limitation, and resistant when grown with an excess of either NHC1 or glutamine. Glutamine synthetase activity was required for expression of the methylammonium-sensitive phenotype. Mutants were isolated which were resistant to 100 m-methylammonium, even when grown under nitrogen limitation. P1 bacteriophage transduction and F′ complementation analysis revealed that the resistance-conferring mutations mapped either inside the structural gene and/or elsewhere in the chromosome. Glutamine synthetase was purified from the wild-type and from some of the mutant strains. Strains carrying -linked mutations that were solely responsible for the methylammonium-resistant phenotype yielded an altered enzyme, which was less active biosynthetically with either ammonium or methylammonium as substrate. Sensitivity to methylammonium appeared to be due to synthesis of γ-glutamylmethyl-amide by glutamine synthetase, which was synthesized poorly, if at all, by mutants carrying an altered glutamine synthetase enzyme.

Loading

Article metrics loading...

/content/journal/micro/10.1099/00221287-133-6-1631
1987-06-01
2019-10-17
Loading full text...

Full text loading...

http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-133-6-1631
Loading
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error