Insights into RNA polymerase catalysis and adaptive evolution gained from mutational analysis of a locus conferring rifampicin resistance.

ABSTRACT: S531 of Escherichia coli RNA polymerase (RNAP) β subunit is a part of RNA binding domain in transcription complex. While highly conserved, S531 is not involved in interactions within the transcription complex as suggested by X-ray analysis. To understand the basis for S531 conservation we performed systematic mutagenesis of this residue. We find that the most of the mutations significantly decreased initiation-to-elongation transition by RNAP. Surprisingly, some changes enhanced the production of full-size transcripts by suppressing abortive loss of short RNAs. S531-R increased transcript retention by establishing a salt bridge with RNA, thereby explaining the R substitution at the equivalent position in extremophilic organisms, in which short RNAs retention is likely to be an issue. Gener

SUBMITTER: Yurieva O 

PROVIDER: S-EPMC5737076 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature