Molecular Mechanism of Processive 3' to 5' RNA Translocation in the Active Subunit of the RNA Exosome Complex.

ABSTRACT: Recent experimental studies revealed structural details of 3' to 5' degradation of RNA molecules, performed by the exosome complex. ssRNA is channeled through its multisubunit ring-like core into the active site tunnel of its key exonuclease subunit Rrp44, which acts both as an enzyme and a motor. Even in isolation, Rrp44 can pull and sequentially cleave RNA nucleotides, one at a time, without any external energy input and release a final 3-5 nucleotide long product. Using molecular dynamics simulations, we identify the main factors that control these processes. Our free energy calculations reveal that RNA transfer from solution into the active site of Rrp44 is highly favorable, but dependent on the length of the RNA strand. While RNA strands formed by 5 nucleotides or more correspond to a

SUBMITTER: Vukovic L 

PROVIDER: S-EPMC4988868 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature