Determinants of the c-terminal domain of the Escherichia coli RNA polymerase a subunit important for transcription at class I cyclic AMP receptor protein-dependent promoters
Savery, N.J.; Lloyd, G.S.; Busby, S.J.W.
Journal of Bacteriology 184(8): 73-80
Amino acid side chains important for class I cyclic AMP receptor protein (CRP)-dependent transcription in Escherichia coli were identified by alanine scanning of the RNA polymerase a subunit C-terminal domain (aCTD). Class I CRP-dependent transcription from the CC(-61.5) promoter or the lacP1 promoter was affected by substitutions in 3 regions of aCTD: the 287 determinant, which contacts CRP during class II CRP-dependent transcription; the 265 determinant, which is important for aCTD-DNA interactions, including those required for class II CRP-dependent transcription; and the 261 determinant. CRP contacted the same target in aCTD, the 287 determinant, at class I and class II CRP-dependent promoters. The relative contributions of individual residues within the 265 determinant depended on promoter sequence.