Mechanism of protein-guided folding of the active site U2/U6 RNA during spliceosome activation.

Cole Townsend, Majety N Leelaram, Dmitry E Agafonov, Olexandr Dybkov, Cindy L Will, Karl Bertram, Henning Urlaub, Berthold Kastner, Holger Stark, Reinhard Lührmann

Science (New York, N.Y.) 2020 Dec 18

filter terms:

Spliceosome activation involves extensive protein and RNA rearrangements that lead to formation of a catalytically active U2/U6 RNA structure. At present, little is known about the assembly pathway of the latter and the mechanism whereby proteins aid its proper folding. Here, we report the cryo-electron microscopy structures of two human, activated spliceosome precursors (that is, pre-Bact complexes) at core resolutions of 3.9 and 4.2 angstroms. These structures elucidate the order of the numerous protein exchanges that occur during activation, the mutually exclusive interactions that ensure the correct order of ribonucleoprotein rearrangements needed to form the U2/U6 catalytic RNA, and the stepwise folding pathway of the latter. Structural comparisons with mature Bact complexes reveal the molecular mechanism whereby a conformational change in the scaffold protein PRP8 facilitates final three-dimensional folding of the U2/U6 catalytic RNA. Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Citation

Cole Townsend, Majety N Leelaram, Dmitry E Agafonov, Olexandr Dybkov, Cindy L Will, Karl Bertram, Henning Urlaub, Berthold Kastner, Holger Stark, Reinhard Lührmann. Mechanism of protein-guided folding of the active site U2/U6 RNA during spliceosome activation. Science (New York, N.Y.). 2020 Dec 18;370(6523)