FIG. 8.

In vitro transcription activity of mutant σ^A-RNA polymerase holoenzyme, with Arg-103 of σ^A replaced with Lys (K), Met (M), Ala (A), or Glu (E). The method used for in vitro transcription is the same as that described for the truncated σ^A. The mutant σ^A-RNA polymerases assayed are shown at the top. The arrowheads indicate the two mRNA transcripts (291 and 451 bases long) generated from the G3b promoter. The value below each lane indicates the relative transcription activity of the assayed RNA polymerase, with that of the WT σ^A-RNA polymerase referred to as 100%. The standard deviation for three individual tests was less than 10%.