RT Journal Article SR Electronic(1) A1 Servín-González, Luis A1 Ortiz, Myriam A1 González, Alicia A1 Bastarrachea, FernandoYR 1987 T1 glnA Mutations Conferring Resistance to Methylammonium in Escherichia coli K12 JF Microbiology, VO 133 IS 6 SP 1631 OP 1639 DO https://doi.org/10.1099/00221287-133-6-1631 PB Microbiology Society, SN 1465-2080, AB Summary: Cells of Escherichia coli K12 were sensitive to 100 mm-methylammonium when cultured under nitrogen limitation, and resistant when grown with an excess of either NH4C1 or glutamine. Glutamine synthetase activity was required for expression of the methylammonium-sensitive phenotype. Mutants were isolated which were resistant to 100 mm-methylammonium, even when grown under nitrogen limitation. P1 bacteriophage transduction and F′ complementation analysis revealed that the resistance-conferring mutations mapped either inside the glnA structural gene and/or elsewhere in the E. coli chromosome. Glutamine synthetase was purified from the wild-type and from some of the mutant strains. Strains carrying glnA-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., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-133-6-1631