5zwn
From Proteopedia
Cryo-EM structure of the yeast pre-B complex at an average resolution of 3.3 angstrom (Part II: U1 snRNP region)
Structural highlights
Function[PRP42_YEAST] Essential component of the U1 snRNP particle, which recognizes and binds the 5'-splice site of pre-mRNA. Together with other non-snRNP factors, U1 snRNP forms the spliceosomal commitment complex, that targets pre-mRNA to the splicing pathway. U1 snRNP is cotranscriptionally recruited to intron-containing genes. Required for U1 snRNP biogenesis.[1] [2] [SMD1_YEAST] Involved in pre-mRNA splicing. Binds snRNA U1, U2, U4 and U5 which contain a highly conserved structural motif called the Sm binding site. Also binds telomerase RNA and is required for its accumulation.[3] [4] [RU17_YEAST] Involved in nuclear mRNA splicing. [PRP39_YEAST] Function prior to stable branch point recognition by the U1 snRNP particle to facilitate or stabilize the U1 snRNP/5'-splice site interaction. Has a direct role in the assembly or function of a catalytically active spliceosome. [SNU56_YEAST] Component of the U1 snRNP particle, which recognizes and binds the 5'-splice site of pre-mRNA. Together with other non-snRNP factors, U1 snRNP forms the spliceosomal commitment complex, that targets pre-mRNA to the splicing pathway. [SNU71_YEAST] Component of the U1 snRNP particle, which recognizes and binds the 5'-splice site of pre-mRNA. Together with other non-snRNP factors, U1 snRNP forms the spliceosomal commitment complex, that targets pre-mRNA to the splicing pathway.[5] [SMD2_YEAST] Involved in pre-mRNA splicing. Binds snRNA U1, U2, U4 and U5 which contain a highly conserved structural motif called the Sm binding site. [PRP28_YEAST] ATP-dependent RNA helicase involved in mRNA splicing. May destabilize the U1/5'-splice site duplex to permit an effective competition for the 5'-splice site by the U6 snRNA, resulting in the switch between U1 and U6 at the 5'-splice site. May also act to unwind the U4/U6 base-pairing interaction in the U4/U6/U5 snRNP, facilitating the first covalent step of splicing.[6] [7] [8] [RUXF_YEAST] Involved in pre-mRNA splicing. Binds snRNA U1, U2, U4 and U5 which contain a highly conserved structural motif called the Sm binding site. [RUXE_YEAST] Involved in pre-mRNA splicing. Binds and is required for the stability of snRNA U1, U2, U4 and U5 which contain a highly conserved structural motif called the Sm binding site. Involved in cap modification.[9] [NAM8_YEAST] Acts as a suppressor of mitochondrial splicing deficiencies when overexpressed. Could be a non-essential component of the mitochondrial splicing machinery. [RU1C_YEAST] 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. YHC1/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 commitment or early (E) complex formation by stabilizing the base pairing of the 5' end of the U1 snRNA and the 5' splice-site region.[10] [11] [12] [LUC7_YEAST] Component of the U1 snRNP particle, which recognizes and binds the 5'-splice site of pre-mRNA. Together with other non-snRNP factors, U1 snRNP forms the spliceosomal commitment complex, that targets pre-mRNA to the splicing pathway.[13] [14] [RSMB_YEAST] Involved in pre-mRNA splicing. Binds snRNA U1, U2, U4 and U5 which contain a highly conserved structural motif called the Sm binding site. [SMD3_YEAST] Involved in pre-mRNA splicing. Binds snRNA U1, U2, U4 and U5 which contain a highly conserved structural motif called the Sm binding site. Also binds telomerase RNA and is required for its accumulation.[15] [16] [RUXG_YEAST] Involved in pre-mRNA splicing. Binds snRNA U1, U2, U4 and U5 which contain a highly conserved structural motif called the Sm binding site. [RU1A_YEAST] Involved in nuclear mRNA splicing. The principal role of the U1A is to help fold or maintain U1 RNA in an active configuration. It 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.[17] [18] Publication Abstract from PubMedThe precatalytic spliceosome (B complex) is preceded by the pre-B complex. Here we report the cryo-electron microscopy structures of the Saccharomyces cerevisiae pre-B and B complexes at average resolutions of 3.3 to 4.6 and 3.9 angstroms, respectively. In the pre-B complex, the duplex between the 5' splice site (5'SS) and U1 small nuclear RNA (snRNA) is recognized by Yhc1, Luc7, and the Sm ring. In the B complex, U1 small nuclear ribonucleoprotein is dissociated, the 5'-exon-5'SS sequences are translocated near U6 snRNA, and three B-specific proteins may orient the precursor messenger RNA. In both complexes, U6 snRNA is anchored to loop I of U5 snRNA, and the duplex between the branch point sequence and U2 snRNA is recognized by the SF3b complex. Structural analysis reveals the mechanism of assembly and activation for the yeast spliceosome. Structures of the fully assembled Saccharomyces cerevisiae spliceosome before activation.,Bai R, Wan R, Yan C, Lei J, Shi Y Science. 2018 Jun 29;360(6396):1423-1429. doi: 10.1126/science.aau0325. Epub 2018, May 24. PMID:29794219[19] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Large Structures | RNA helicase | Saccharomyces cerevisiae s288c | Bai, R | Lei, J | Shi, Y | Wan, R | Yan, C | Assemply | Pre-b complex | Spliceosme | Splicing | U1 snrnp
