Fig. 3
From: Structures of the human pre-catalytic spliceosome and its precursor spliceosome
Structural comparison of the protein components between the human pre-B complex and the human B complex. a Structural changes of Brr2 and Prp8 in the pre-B-to-B transition. These changes are based on the alignment of U5 snRNA between the pre-B and B complexes. Brr2 is translocated by 120–320 Å and flipped by nearly 180 degrees. The Jab1 domain of Prp8, which stably associates with Brr2, is similarly translocated. The RNaseH-like domain of Prp8 is rotated by about 180 degrees. The four domains in the core of Prp8 (Fingers/Palm, Thumb/X, Linker, endonuclease-like) undergo varying degrees of positional shift. b A close-up view of Prp8 in the pre-B-to-B transition. Notably, the U5 Sm ring, U5-40K, and the N-domain of Prp8 remain largely unchanged. All other domains of Prp8 undergo noticeable structural rearrangements, which make the inter-domain organization of Prp8 more compact. c Structural changes of select proteins in the U4/U6.U5 tri-snRNP. Most proteins of the tri-snRNP undergo translocation and conformational changes in the pre-B-to-B transition. Highlighted here are Prp3, Prp4, Prp6, and Prp31, each of which undergoes pronounced translocation. The C-terminal fragment of Prp3 and the TPR repeats of Prp6 are shifted by approximately 25 and 35 Å, respectively
