Fig. 1: Cryo-EM structures of six distinct conformational states of the human Bact complex.
From: Molecular basis for the activation of human spliceosome
a Schematic representation of the activation process of the human spliceosome. The B complex, containing U5.U4/U6 tri-snRNP, is remodeled by the RNA helicase BRR2, resulting in the release of U4 snRNP and recruitment of the NTC and NTR complexes. In the Bact-to-B* transition catalyzed by PRP2, the BS is brought into the close proximity of 5′SS for the branching reaction. b Cryo-EM structures of six distinct intermediate states between the B and B* complexes. These complexes, named pre-Bact, Bact-I, Bact-II, Bact-III, Bact-IV, and post-Bact, are resolved at average resolutions of 3.4, 3.0, 4.2, 3.0, 3.3, and 3.0 Å, respectively. All complexes, with components displayed in color-coded surface representation, are shown in the same orientation. c Cryo-EM structure of the human C complex at an average resolution of 3.4 Å. All structural images in this manuscript were prepared using ChimeraX71 and PyMol72.
