High-Resolution Phenotypic Landscape of the RNA Polymerase II Trigger Loop.

ABSTRACT: The active sites of multisubunit RNA polymerases have a "trigger loop" (TL) that multitasks in substrate selection, catalysis, and translocation. To dissect the Saccharomyces cerevisiae RNA polymerase II TL at individual-residue resolution, we quantitatively phenotyped nearly all TL single variants en masse. Three mutant classes, revealed by phenotypes linked to transcription defects or various stresses, have distinct distributions among TL residues. We find that mutations disrupting an intra-TL hydrophobic pocket, proposed to provide a mechanism for substrate-triggered TL folding through destabilization of a catalytically inactive TL state, confer phenotypes consistent with pocket disruption and increased catalysis. Furthermore, allele-specific genetic interactions among TL and TL-proxima

SUBMITTER: Qiu C 

PROVIDER: S-EPMC5127505 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature