5mqf
From Proteopedia
Cryo-EM structure of a human spliceosome activated for step 2 of splicing (C* complex)
Structural highlights
DiseasePRP8_HUMAN Defects in PRPF8 are the cause of retinitis pigmentosa type 13 (RP13) [MIM:600059. RP leads to degeneration of retinal photoreceptor cells. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well. RP13 inheritance is autosomal dominant.[1] [2] [:][3] [4] FunctionPRP8_HUMAN Central component of the spliceosome, which may play a role in aligning the pre-mRNA 5'- and 3'-exons for ligation. Interacts with U5 snRNA, and with pre-mRNA 5'-splice sites in B spliceosomes and 3'-splice sites in C spliceosomes. 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[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. Loading citation details.. Citations No citations found See Also
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