title: Elastic coupling between RNA degradation and unwinding by an exoribonuclease.
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.
authors: Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801, USA.
authors: Gwangrog
authors: G
authors: Lee
authors: Matthew A
authors: MA
authors: Bratkowski
authors: Fang
authors: F
authors: Ding
authors: Ailong
authors: A
authors: Ke
authors: Taekjip
authors: T
authors: Ha
mesh_terms: D020029:Base Pairing; D005095:Exoribonucleases / Q000378:metabolism*; D063326:Exosome Multienzyme Ribonuclease Complex; D020871:RNA Stability; D012331:RNA, Fungal / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: D012331:RNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D005095:Exoribonucleases; D063326:Exosome Multienzyme Ribonuclease Complex; C542283:DIS3 protein, S cerevisiae