Fig. 5
From: Structures of the human pre-catalytic spliceosome and its precursor spliceosome
Structural comparison of the human and S. cerevisiae pre-B-to-B transitions. a Comparison of the overall structures between the human and S. cerevisiae pre-B complexes. Compared to S. cerevisiae,14 the overall appearance of the human pre-B complex is quite different, and the location of U1 snRNP relevant to tri-snRNP has shifted drastically. The retention and splicing (RES) complex is present in the S. cerevisiae pre-B and B complexes, but not in the human complexes. b Comparison of the RNA elements in the human and S. cerevisiae pre-B-to-B transitions. Loop I of U5 snRNA remains unoccupied in the human pre-B complex but forms a duplex with U6 snRNA in the S. cerevisiae pre-B complex.14 In the human B complex, the 5’SS and the 5’-exon have already been recognized by U6 snRNA and loop I of U5 snRNA; but in S. cerevisiae, the 5’SS is yet to be recognized by U6 snRNA and loop I of U5 snRNA remains engaged with U6 snRNA14
