4pkd
From Proteopedia
U1-70k in complex with U1 snRNA stem-loops 1 and U1-A RRM in complex with stem-loop 2
Structural highlights
FunctionRU17_HUMAN Mediates the splicing of pre-mRNA by binding to the loop I region of U1-snRNA. The truncated isoforms cannot bind U1-snRNA.SNRPA_PIG Component of the spliceosomal U1 snRNP, which is essential for recognition of the pre-mRNA 5' splice-site and the subsequent assembly of the spliceosome. U1 snRNP is the first snRNP to interact with pre-mRNA. This interaction is required for the subsequent binding of U2 snRNP and the U4/U6/U5 tri-snRNP. SNRPA binds stem loop II of U1 snRNA. In a snRNP-free form (SF-A) may be involved in coupled pre-mRNA splicing and polyadenylation process. May bind preferentially to the 5'-UGCAC-3' motif on RNAs (By similarity). Publication Abstract from PubMedU1 snRNP binds to the 5' exon-intron junction of pre-mRNA and thus plays a crucial role at an early stage of pre-mRNA splicing. We present two crystal structures of engineered U1 sub-structures, which together reveal at atomic resolution an almost complete network of protein-protein and RNA-protein interactions within U1 snRNP, and show how the 5' splice site of pre-mRNA is recognised by U1 snRNP. The zinc-finger of U1-C interacts with the duplex between pre-mRNA and the 5'-end of U1 snRNA. The binding of the RNA duplex is stabilized by hydrogen bonds and electrostatic interactions between U1-C and the RNA backbone around the splice junction but U1-C makes no base-specific contacts with pre-mRNA. The structure, together with RNA binding assays, shows that the selection of 5'-splice site nucleotides by U1 snRNP is achieved predominantly through basepairing with U1 snRNA whilst U1-C fine-tunes relative affinities of mismatched 5'-splice sites. Crystal structure of human U1 snRNP, a small nuclear ribonucleoprotein particle, reveals the mechanism of 5' splice site recognition.,Kondo Y, Oubridge C, van Roon AM, Nagai K Elife. 2015 Jan 2;4. doi: 10.7554/eLife.04986. PMID:25555158[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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