Elastic coupling between RNA degradation and unwinding by an exoribonuclease

Gwangrog Lee, Matthew A. Bratkowski, Fang Ding, Ailong Ke, Taekjip Ha

Research output: Contribution to journalArticlepeer-review

Abstract

Rrp44 (Dis3) is a key catalytic subunit of the yeast exosome complex and can processively digest structured RNA one nucleotide at a time in the 3′ to 5′ direction. Its motor function is powered by the energy released from the hydrolytic nuclease reaction instead of adenosine triphosphate hydrolysis as in conventional helicases. Single-molecule fluorescence analysis revealed that instead of unwinding RNA in single base pair steps, Rrp44 accumulates the energy released by multiple single nucleotide step hydrolysis reactions until about four base pairs are unwound in a burst. Kinetic analyses showed that RNA unwinding, not cleavage or strand release, determines the overall RNA degradation rate and that the unwinding step size is determined by the nonlinear elasticity of the Rrp44/RNA complex, but not by duplex stability.

Original languageEnglish (US)
Pages (from-to)1726-1729
Number of pages4
JournalScience
Volume336
Issue number6089
DOIs
StatePublished - Jun 29 2012

ASJC Scopus subject areas

  • General

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