High intrinsic hydrolytic activity of cyanobacterial RNA polymerase compensates for the absence of transcription proofreading factors

Riaz-Bradley, Amber, James, Katherine and Yuzenkova, Yulia (2020) High intrinsic hydrolytic activity of cyanobacterial RNA polymerase compensates for the absence of transcription proofreading factors. Nucleic Acids Research, 48 (3). pp. 1341-1352. ISSN 0305-1048

[img]
Preview
Text (Advance online version)
gkz1130.pdf - Published Version
Available under License Creative Commons Attribution 4.0.

Download (2MB) | Preview
Official URL: https://doi.org/10.1093/nar/gkz1130

Abstract

The vast majority of organisms possess transcription elongation factors, the functionally similar bacterial Gre and eukaryotic/archaeal TFIIS/TFS. Their main cellular functions are to proofread errors of transcription and to restart elongation via stimulation of RNA hydrolysis by the active centre of RNA polymerase (RNAP). However, a number of taxons lack these factors, including one of the largest and most ubiquitous groups of bacteria, cyanobacteria. Using cyanobacterial RNAP as a model, we investigated alternative mechanisms for maintaining a high fidelity of transcription and for RNAP arrest prevention. We found that this RNAP has very high intrinsic proofreading activity, resulting in nearly as low a level of in vivo mistakes in RNA as Escherichia coli. Features of the cyanobacterial RNAP hydrolysis are reminiscent of the Gre-assisted reaction—the energetic barrier is similarly low, and the reaction involves water activation by a general base. This RNAP is resistant to ubiquitous and most regulatory pausing signals, decreasing the probability to go off-pathway and thus fall into arrest. We suggest that cyanobacterial RNAP has a specific Trigger Loop domain conformation, and isomerises easier into a hydrolytically proficient state, possibly aided by the RNA 3′-end. Cyanobacteria likely passed these features of transcription to their evolutionary descendants, chloroplasts.

Item Type: Article
Subjects: C700 Molecular Biology, Biophysics and Biochemistry
F100 Chemistry
F200 Materials Science
Department: Faculties > Health and Life Sciences > Applied Sciences
Depositing User: Elena Carlaw
Date Deposited: 21 Jan 2020 16:41
Last Modified: 18 Mar 2020 09:30
URI: http://nrl.northumbria.ac.uk/id/eprint/41965

Actions (login required)

View Item View Item

Downloads

Downloads per month over past year

View more statistics