BACILLUS-SUBTILIS GNT REPRESSOR MUTANTS THAT DIMINISH GLUCONATE-BINDING ABILITY

The Bacillus subtilis gnt operon is negatively regulated by GntR, whic h is antagonized by gluconate. Three GntR mutants with diminished gluc onate-binding ability were obtained. Two were missense mutants (Met-20 9 to Ile and Ser-230 to Leu), whereas the third had a deletion of the C-terminal 23 amino acids. The mutant GntR proteins were unable to bec ome properly detached from the gnt operator even in the presence of gl uconate.