5mqf
Cryo-EM structure of a human spliceosome activated for step 2 of splicing (C* complex)
Structural highlights
FunctionPPIE_HUMAN PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. Combines RNA-binding and PPIase activities. May be involved in muscle- and brain-specific processes. May be involved in pre-mRNA splicing. Publication Abstract from PubMedSpliceosome rearrangements facilitated by RNA helicase PRP16 before catalytic step two of splicing are poorly understood. Here we report a 3D cryo-electron microscopy structure of the human spliceosomal C complex stalled directly after PRP16 action (C*). The architecture of the catalytic U2-U6 ribonucleoprotein (RNP) core of the human C* spliceosome is very similar to that of the yeast pre-Prp16 C complex. However, in C* the branched intron region is separated from the catalytic centre by approximately 20 A, and its position close to the U6 small nuclear RNA ACAGA box is stabilized by interactions with the PRP8 RNase H-like and PRP17 WD40 domains. RNA helicase PRP22 is located about 100 A from the catalytic centre, suggesting that it destabilizes the spliced mRNA after step two from a distance. Comparison of the structure of the yeast C and human C* complexes reveals numerous RNP rearrangements that are likely to be facilitated by PRP16, including a large-scale movement of the U2 small nuclear RNP. Cryo-EM structure of a human spliceosome activated for step 2 of splicing.,Bertram K, Agafonov DE, Liu WT, Dybkov O, Will CL, Hartmuth K, Urlaub H, Kastner B, Stark H, Luhrmann R Nature. 2017 Feb 16;542(7641):318-323. doi: 10.1038/nature21079. Epub 2017 Jan, 11. PMID:28076346[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also
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