Table 3.

Effects of PCR random mutations on the repression ofwapA transcription by salt stress

Plasmidaβ-Galactosidase sp act (U/mg of protein)b
High saltLow salt
pWP266 (wild type)4003,700
pWP266.2S (T−24C)1,3254,180
pWP266.3S (T+12)2,4604,780
pWP266.7S (C+11T)3,5704,780
pWP266.19S (C+20T)4,5002,800
pWP266.32S (C−21A)2,1253,900
  • a See Fig. 5 for positions of the mutations.

  • b Cells were grown in MB liquid medium containing 100 mM (low salt) or 0.7 M (high salt) disodium succinate. β-Galactosidase activities were determined 3 h after the end of the exponential growth phase.