Table 1.

Effects of position +3 promoter mutations on expression and regulation of short and longcarAp1::lacZ operon fusions

Strain (carAp1 mutation)Promoter region lengthβ-Galactosidase activity (nmol/min/mg)aFold regulation
UracilUMP
CLT5174 (none [wtb])Shortc 9922,8202.8
CLT5175 (T to G)Short3,6104,9101.4
CLT5177 (T to C)Short2,0402,4301.2
CLT5192 (none [wt])Longd 1322,34018
CLT5202 (T to G)Long5633,4806.2
CLT5203 (T to C)Long3052,7108.9
  • a Values are the means of at least three independent determinations with a variation of <8%. Doubling times were 46 ± 2 min for cells grown on uracil and 68 ± 2 min for cells grown on UMP.

  • b wt, wild type.

  • c The short carAB P1 promoter region contained bp −58 to +40.

  • d The long carAB P1 promoter region contained bp −355 to +40.