This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
3jcm
From Proteopedia
| Line 1: | Line 1: | ||
==Cryo-EM structure of the spliceosomal U4/U6.U5 tri-snRNP== | ==Cryo-EM structure of the spliceosomal U4/U6.U5 tri-snRNP== | ||
| - | <StructureSection load='3jcm' size='340' side='right' caption='[[3jcm]], [[Resolution|resolution]] 3.80Å' scene=''> | + | <StructureSection load='3jcm' size='340' side='right'caption='[[3jcm]], [[Resolution|resolution]] 3.80Å' scene=''> |
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>[[3jcm]] is a 34 chain structure with sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae_s288c Saccharomyces cerevisiae s288c]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3JCM OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3JCM FirstGlance]. <br> | <table><tr><td colspan='2'>[[3jcm]] is a 34 chain structure with sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae_s288c Saccharomyces cerevisiae s288c]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3JCM OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3JCM FirstGlance]. <br> | ||
| Line 26: | Line 26: | ||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
| + | [[Category: Large Structures]] | ||
[[Category: RNA helicase]] | [[Category: RNA helicase]] | ||
[[Category: Saccharomyces cerevisiae s288c]] | [[Category: Saccharomyces cerevisiae s288c]] | ||
Revision as of 06:15, 16 October 2019
Cryo-EM structure of the spliceosomal U4/U6.U5 tri-snRNP
Structural highlights
Function[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. [LSM5_YEAST] Component of LSm protein complexes, which are involved in RNA processing and may function in a chaperone-like manner. Component of the cytoplasmic LSM1-LSM7 complex which is thought to be involved in mRNA degradation by activating the decapping step. Component of the nuclear LSM2-LSM8 complex, which is involved in splicing of nuclear mRNAs. LSM2-LSM8 associates with multiple snRNP complexes containing the U6 snRNA (U4/U6 snRNP, U4/U6.U5 snRNP, and free U6 snRNP). It binds directly to the U6 snRNA and plays a role in the biogenesis and stability of the U6 snRNP and U4/U6 snRNP complexes. It probably also is involved degradation of nuclear pre-mRNA by targeting them for decapping. LSM5 binds specifically to the 3'-terminal U-tract of U6 snRNA. LSM2-LSM8 probably is involved in processing of pre-tRNAs, pre-rRNAs and U3 snoRNA. LSM5, probably in a complex that contains LSM2-LSM7 but not LSM1 or LSM8, associates with the precursor of the RNA component of RNase P (pre-P RNA) and may be involved in maturing pre-P RNA. LSM5 is required for processing of pre-tRNAs, pre-rRNAs and U3 snoRNA.[1] [2] [3] [4] [5] [SNU13_YEAST] Common component of the spliceosome and rRNA processing machinery. In association with the spliceosomal U4/U6.U5 tri-snRNP particle, required for splicing of pre-mRNA. In association with box C/D snoRNPs, required for processing of pre-ribosomal RNA (rRNA) and site-specific 2'-O-methylation of substrate RNAs. Essential for the accumulation and stability of U4 snRNA, U6 snRNA, and box C/D snoRNAs.[6] [7] [8] [LSM8_YEAST] Component of the nuclear LSM2-LSM8 complex, which is involved in splicing of nuclear mRNAs. LSM2-LSM8 associates with multiple snRNP complexes containing the U6 snRNA (U4/U6 snRNP, spliceosomal U4/U6.U5 snRNP, and free U6 snRNP). It binds directly to the U6 snRNA and plays a role in the biogenesis and stability of the U6 snRNP and U4/U6 snRNP complexes. It probably also is involved degradation of nuclear pre-mRNA by targeting them for decapping. LSM2-LSM8 probably is involved in processing of pre-tRNAs, pre-rRNAs and U3 snoRNA. LSM2 is required for processing of pre-tRNAs, pre-rRNAs and U3 snoRNA.[9] [10] [11] [PRP4_YEAST] Involved in RNA splicing. Is required for the association of U4/U6 snRNP with U5 snRNP in an early step of spliceosome assembly. [LSM7_YEAST] Component of LSm protein complexes, which are involved in RNA processing and may function in a chaperone-like manner. Component of the cytoplasmic LSM1-LSM7 complex which is thought to be involved in mRNA degradation by activating the decapping step. Component of the nuclear LSM2-LSM8 complex, which is involved in splicing of nuclear mRNAs. LSM2-LSM8 associates with multiple snRNP complexes containing the U6 snRNA (U4/U6 snRNP, spliceosomal U4/U6.U5 snRNP, and free U6 snRNP). It binds directly to the U6 snRNA and plays a role in the biogenesis and stability of the U6 snRNP and U4/U6 snRNP complexes. It probably also is involved degradation of nuclear pre-mRNA by targeting them for decapping. LSM7 binds specifically to the 3'-terminal U-tract of U6 snRNA. LSM2-LSM8 probably is involved in processing of pre-tRNAs, pre-rRNAs and U3 snoRNA. LSM7, probably in a complex that contains LSM2-LSM7 but not LSM1 or LSM8, associates with the precursor of the RNA component of RNase P (pre-P RNA) and may be involved in maturing pre-P RNA.[12] [13] [14] [PRP8_YEAST] Required for pre-spliceosome formation, which is the first step of pre-mRNA splicing. This protein is associated with snRNP U5. Has a role in branch site-3' splice site selection. Associates with the branch site-3' splice 3'-exon region. Also has a role in cell cycle.[15] [16] [17] [18] [LSM2_YEAST] Component of LSm protein complexes, which are involved in RNA processing and may function in a chaperone-like manner. Component of the cytoplasmic LSM1-LSM7 complex which is thought to be involved in mRNA degradation by activating the decapping step. Component of the nuclear LSM2-LSM8 complex, which is involved in splicing of nuclear mRNAs. LSM2-LSM8 associates with multiple snRNP complexes containing the U6 snRNA (U4/U6 snRNP, U4/U6.U5 snRNP, and free U6 snRNP). It binds directly to the U6 snRNA and plays a role in the biogenesis and stability of the U6 snRNP and U4/U6 snRNP complexes. It probably also is involved degradation of nuclear pre-mRNA by targeting them for decapping. LSM2 binds specifically to the 3'-terminal U-tract of U6 snRNA. LSM2-LSM8 probably is involved in processing of pre-tRNAs, pre-rRNAs and U3 snoRNA. LSM2, probably in a complex that contains LSM2-LSM7 but not LSM1 or LSM8, associates with the precursor of the RNA component of RNase P (pre-P RNA) and may be involved in maturing pre-P RNA. LSM2 is required for processing of pre-tRNAs, pre-rRNAs and U3 snoRNA.[19] [20] [21] [22] [23] [LSM4_YEAST] Component of LSm protein complexes, which are involved in RNA processing and may function in a chaperone-like manner. Component of the cytoplasmic LSM1-LSM7 complex which is thought to be involved in mRNA degradation by activating the decapping step. Component of the nuclear LSM2-LSM8 complex, which is involved in splicing of nuclear mRNAs. LSM2-LSM8 associates with multiple spliceosome snRNP complexes containing the U6 snRNA (U4/U6 snRNP, U4/U6.U5 snRNP, and free U6 snRNP). It binds directly to the U6 snRNA and plays a role in the biogenesis and stability of the U6 snRNP and U4/U6 snRNP complexes. It probably also is involved degradation of nuclear pre-mRNA by targeting them for decapping. LSM4 binds specifically to the 3'-terminal U-tract of U6 snRNA. LSM2-LSM8 probably is involved in processing of pre-tRNAs, pre-rRNAs and U3 snoRNA. LSM4, probably in a complex that contains LSM2-LSM7 but not LSM1 or LSM8, associates with the precursor of the RNA component of RNase P (pre-P RNA) and may be involved in maturing pre-P RNA. LSM4 is required for processing of pre-tRNAs, pre-rRNAs and U3 snoRNA.[24] [25] [26] [27] [28] [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. [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. [DIB1_YEAST] Essential role in pre-mRNA splicing. Also essential for entry into mitosis (G2/M progression) as well as for chromosome segregation during mitosis. [PRP31_YEAST] Promotes the association of the U4/U6.U5 tri-snRNP particle with pre-spliceosomes to form the mature spliceosomal complex.[29] [BRR2_YEAST] RNA helicase that plays an essential role in pre-mRNA splicing as component of the U5 snRNP and U4/U6-U5 tri-snRNP complexes. Involved in spliceosome assembly, activation and disassembly. Mediates changes in the dynamic network of RNA-RNA interactions in the spliceosome. Catalyzes the ATP-dependent unwinding of U4/U6 RNA duplices, an essential step in the assembly of a catalytically active spliceosome.[30] [31] [32] [33] [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.[34] [35] [LSM6_YEAST] Component of LSm protein complexes, which are involved in RNA processing and may function in a chaperone-like manner, facilitating the efficient association of RNA processing factors with their substrates. Component of the cytoplasmic LSM1-LSM7 complex, which is thought to be involved in mRNA degradation by activating the decapping step in the 5'-to-3' mRNA decay pathway. In association with PAT1, LSM1-LSM7 binds directly to RNAs near the 3'-end and prefers oligoadenylated RNAs over polyadenylated RNAs. Component of the nuclear LSM2-LSM8 complex, which is involved in splicing of nuclear mRNAs. LSM2-LSM8 associates with multiple snRNP complexes containing the U6 snRNA (U4/U6 di-snRNP, spliceosomal U4/U6.U5 tri-snRNP, and free U6 snRNP). It binds directly to the 3'-terminal U-tract of U6 snRNA and plays a role in the biogenesis and stability of the U6 snRNP and U4/U6 snRNP complexes. LSM2-LSM8 probably also is involved degradation of nuclear pre-mRNA by targeting them for decapping, and in processing of pre-tRNAs, pre-rRNAs and U3 snoRNA. Component of a nucleolar LSM2-LSM7 complex, which associates with the precursor of the RNA component of RNase P (pre-P RNA) and with the small nucleolar RNA (snoRNA) snR5. It may play a role in the maturation of a subset of nucleolus-associated small RNAs.[36] [37] [38] [39] [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.[40] [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. [SN114_YEAST] Component of the U5 snRNP complex required for pre-mRNA splicing. Binds GTP. [PRP6_YEAST] Participates in pre-mRNA splicing. Part of the U4/U5/U6 tri-snRNP complex, one of the building blocks of the spliceosome. [LSM3_YEAST] Component of LSm protein complexes, which are involved in RNA processing and may function in a chaperone-like manner. Component of the cytoplasmic LSM1-LSM7 complex which is thought to be involved in mRNA degradation by activating the decapping step. Component of the nuclear LSM2-LSM8 complex, which is involved in splicing of nuclear mRNAs. LSM2-LSM8 associates with multiple snRNP complexes containing the U6 snRNA (U4/U6 snRNP, U4/U6.U5 snRNP, and free U6 snRNP). It binds directly to the U6 snRNA and plays a role in the biogenesis and stability of the U6 snRNP and U4/U6 snRNP complexes. It probably also is involved degradation of nuclear pre-mRNA by targeting them for decapping. LSM3 binds specifically to the 3'-terminal U-tract of U6 snRNA. LSM2-LSM8 probably is involved in processing of pre-tRNAs, pre-rRNAs and U3 snoRNA. LSM3, probably in a complex that contains LSM2-LSM7 but not LSM1 or LSM8, associates with the precursor of the RNA component of RNase P (pre-P RNA) and may be involved in maturing pre-P RNA. LSM3 is required for processing of pre-tRNAs, pre-rRNAs and U3 snoRNA.[41] [42] [43] [44] [45] [46] [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.[47] [48] [PRP3_YEAST] Participates in pre-mRNA splicing. Part of the U4/U5/U6 tri-snRNP complex, one of the building blocks of the spliceosome.[49] Publication Abstract from PubMedSplicing of precursor messenger RNA is accomplished by a dynamic megacomplex known as the spliceosome. Assembly of a functional spliceosome requires a preassembled U4/U6.U5 tri-snRNP complex, which comprises the U5 small nuclear ribonucleoprotein (snRNP), the U4 and U6 small nuclear RNA (snRNA) duplex, and a number of protein factors. Here we report the three-dimensional structure of a Saccharomyces cerevisiae U4/U6.U5 tri-snRNP at an overall resolution of 3.8 angstroms by single-particle electron cryomicroscopy. The local resolution for the core regions of the tri-snRNP reaches 3.0 to 3.5 angstroms, allowing construction of a refined atomic model. Our structure contains U5 snRNA, the extensively base-paired U4/U6 snRNA, and 30 proteins including Prp8 and Snu114, which amount to 8495 amino acids and 263 nucleotides with a combined molecular mass of ~1 megadalton. The catalytic nucleotide U80 from U6 snRNA exists in an inactive conformation, stabilized by its base-pairing interactions with U4 snRNA and protected by Prp3. Pre-messenger RNA is bound in the tri-snRNP through base-pairing interactions with U6 snRNA and loop I of U5 snRNA. This structure, together with that of the spliceosome, reveals the molecular choreography of the snRNAs in the activation process of the spliceosomal ribozyme. The 3.8 A structure of the U4/U6.U5 tri-snRNP: Insights into spliceosome assembly and catalysis.,Wan R, Yan C, Bai R, Wang L, Huang M, Wong CC, Shi Y Science. 2016 Jan 29;351(6272):466-75. doi: 10.1126/science.aad6466. Epub 2016, Jan 7. PMID:26743623[50] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
| ||||||||||||||||||||
