RPA transforms RNase H1 to a bidirectional exoribonuclease for processive RNA-DNA hybrid cleavage.

ABSTRACT: RNase H1 has been acknowledged as an endoribonuclease specializing in the internal degradation of the RNA moiety within RNA-DNA hybrids, and its ribonuclease activity is indispensable in multifaceted aspects of nucleic acid metabolism. However, the molecular mechanism underlying RNase H1-mediated hybrid cleavage remains inadequately elucidated. Herein, using single-molecule approaches, we probe the dynamics of the hybrid cleavage by Saccharomyces cerevisiae RNase H1. Remarkably, a single RNase H1 enzyme displays 3'-to-5' exoribonuclease activity. The directional RNA degradation proceeds processively and yet discretely, wherein unwinding approximately 6-bp hybrids as a prerequisite for two consecutive 3-nt RNA excisions limits the overall rate within each catalytic cycle. Moreover, Replicat

SUBMITTER: Li Y 

PROVIDER: S-EPMC11358518 | biostudies-literature | 2024 Aug

REPOSITORIES: biostudies-literature