Format

Send to

Choose Destination
Nucleic Acids Res. 2016 Feb 18;44(3):1298-308. doi: 10.1093/nar/gkv1521. Epub 2016 Jan 4.

Lineage-specific variations in the trigger loop modulate RNA proofreading by bacterial RNA polymerases.

Author information

1
Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov square 2, Moscow 123182, Russia.
2
Department of Biochemistry, University of Turku, Turku 20014, Finland.
3
Institute of Biotechnology, Vilnius University, Vilnius 02241, Lithuania.
4
Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov square 2, Moscow 123182, Russia akulb@img.ras.ru.

Abstract

RNA cleavage by bacterial RNA polymerase (RNAP) has been implicated in transcriptional proofreading and reactivation of arrested transcription elongation complexes but its molecular mechanism is less understood than the mechanism of nucleotide addition, despite both reactions taking place in the same active site. RNAP from the radioresistant bacterium Deinococcus radiodurans is characterized by highly efficient intrinsic RNA cleavage in comparison with Escherichia coli RNAP. We find that the enhanced RNA cleavage activity largely derives from amino acid substitutions in the trigger loop (TL), a mobile element of the active site involved in various RNAP activities. The differences in RNA cleavage between these RNAPs disappear when the TL is deleted, or in the presence of GreA cleavage factors, which replace the TL in the active site. We propose that the TL substitutions modulate the RNA cleavage activity by altering the TL folding and its contacts with substrate RNA and that the resulting differences in transcriptional proofreading may play a role in bacterial stress adaptation.

PMID:
26733581
PMCID:
PMC4756841
DOI:
10.1093/nar/gkv1521
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center