Fig. 2.

Rifampicin phenotypic resistance from mistranslation is due to variation in the protein target. (A) The RRDR of the β-subunit of RNAP of M. smegmatis. The highlighted residues refer to a glutamine or asparagine residue, that if substituted for glutamate or aspartate, respectively, results in rifampicin resistance of the protein. The relative activity of RNAP isolated from WT or mistranslating strains of M. smegmatis in the presence of rifampicin was measured by rolling circle assay (B) or radioactively labeled multiround in vitro transcription. The gel is representative of multiple experiments, and results are quantified and analyzed in Fig. S7 (C) (*P < 0.05, **P < 0.01, Student t test).