Altered regulation of the glnRA operon in a Bacillus subtilis mutant that produces methionine sulfoximine-tolerant glutamine synthetase

H J Schreier, C A Rostkowski, E M Kelln, Altered regulation of the glnRA operon in a Bacillus subtilis mutant that produces methionine sulfoximine-tolerant glutamine synthetase, J Bacteriol. 1993 Feb;175(3):892-7, DOI: 10.1128/jb.175.3.892-897.1993

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Subjects

Bacillus subfilis
glutamine synthetase (GS)
DL-methionine sulfoximine
Lmethionine-SR-sulfoximine (MSX)

Abstract

A Bacillus subfilis mutant that produced glutamine synthetase (GS) with altered sensitivity to DL-methionine sulfoximine was isolated. The mutation, designated glnA33, was due to a T- A-to-C- G transition, changing valine to alanine at codon 190 within the active-site C domain. Altered regulation was observed for GS activity and antigen and mRNA levels in a B. subtilis glnA33 strain. The mutant enzyme was 28-fold less sensitive to DL-methionine sulfoximine and had a 13.0-fold-higher Km for hydroxylamine and a 4.8-fold-higher Km for glutamate than wild-type GS did.