4pjo
From Proteopedia
Minimal U1 snRNP
Structural highlights
Function[RUXF_HUMAN] Appears to function in the U7 snRNP complex that is involved in histone 3'-end processing. Associated with snRNP U1, U2, U4/U6 and U5. [SMD1_HUMAN] May act as a charged protein scaffold to promote snRNP assembly or strengthen snRNP-snRNP interactions through nonspecific electrostatic contacts with RNA. [RUXG_HUMAN] Appears to function in the U7 snRNP complex that is involved in histone 3'-end processing. Associated with snRNP U1, U2, U4/U6 and U5. [RU1C_HUMAN] Component of the U1 snRNP, which is essential for recognition of the pre-mRNA 5' splice-site and the subsequent assembly of the spliceosome. U1-C is directly involved in initial 5' splice-site recognition for both constitutive and regulated alternative splicing. The interaction with the 5' splice-site seems to precede base-pairing between the pre-mRNA and the U1 snRNA. Stimulates E complex formation by stabilizing the base pairing of the 5' end of the U1 snRNA and the 5' splice-site region.[1] [2] [3] [RSMB_HUMAN] Appears to function in the U7 snRNP complex that is involved in histone 3'-end processing. Associated with snRNP U1, U2, U4/U6 and U5. May have a functional role in the pre-mRNA splicing or in snRNP structure. Binds to the downstream cleavage product (DCP) of histone pre-mRNA in a U7 snRNP dependent manner (By similarity). [RU17_HUMAN] Mediates the splicing of pre-mRNA by binding to the loop I region of U1-snRNA. The truncated isoforms cannot bind U1-snRNA. [SMD3_HUMAN] Appears to function in the U7 snRNP complex that is involved in histone 3'-end processing. Binds to the downstream cleavage product (DCP) of histone pre-mRNA in a U7 snRNP dependent manner.[4] [SMD2_HUMAN] Required for pre-mRNA splicing. Required for snRNP biogenesis (By similarity). [RUXE_HUMAN] Appears to function in the U7 snRNP complex that is involved in histone 3'-end processing. Associated with snRNP U1, U2, U4/U6 and U5. 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[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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