5mps | pdb_00005mps

Structure of a spliceosome remodeled for exon ligation

Loading... Status: waiting for Mol* initialization Structural highlights 5mps is a 30 chain structure with sequence from [1], Atcc 18824 and Saccharomyces cerevisiae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GTP, I6P, K, MG, ZN NonStd Res: UNK Gene: UBC4 (ATCC 18824) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [BUD31_YEAST] Involved in pre-mRNA splicing. Important for bud site selection. [PRP17_YEAST] May function in the second step of pre-mRNA splicing. Regulatory protein involved in replication and mitotic spindle formation and/or maintenance. Required for initiation and completion of S-phase and for initiation and completion of DNA replication. Might be required for the maintenance of microtubules. Essential only at elevated temperatures. [SN114_YEAST] Component of the U5 snRNP complex required for pre-mRNA splicing. Binds GTP. [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. [CLF1_YEAST] Involved in pre-mRNA splicing and cell cycle progression. Required for the spliceosome assembly by promoting the functional integration of the U4/U6.U5 tri-snRNP particle into the U1-, U2-dependent pre-spliceosome. Also recruits PRP19 to the spliceosome, as a component of the NTC complex (or PRP19-associated complex). The association of the NTC complex to the spliceosome mediates conformational rearrangement or stabilizes the structure of the spliceosome after U4 snRNA dissociation, which leads to spliceosome maturation. Required for initiation of the DNA replication by binding the RNA replication origins, probably through its interaction with the origin recognition complex (ORC). [SYF1_YEAST] Involved in pre-mRNA splicing and cell cycle control. As a component of the NTC complex (or PRP19-associated complex), associates to the spliceosome to mediate conformational rearrangement or to stabilize the structure of the spliceosome after U4 snRNA dissociation, which leads to spliceosome maturation. [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. [SYF2_YEAST] Involved in pre-mRNA splicing and cell cycle control. As a component of the NTC complex (or PRP19-associated complex), associates to the spliceosome to mediate conformational rearrangement or to stabilize the structure of the spliceosome after U4 snRNA dissociation, which leads to spliceosome maturation. The cell cycle arrest of SYF2 defective cells may be due to the inefficient splicing of TUB1. [SLT11_YEAST] Involved in pre-mRNA splicing. Facilitates the cooperative formation of U2/U6 helix II in association with stem II in the spliceosome. Binds to RNA. [CWC21_YEAST] Involved in pre-mRNA splicing. May function at or prior to the first catalytic step of splicing at the catalytic center of the spliceosome, together with ISY1. May do so by stabilizing the catalytic center or the position of the RNA substrate. [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. [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. [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. [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. [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. [PRP46_YEAST] Involved in pre-mRNA splicing. May also be required for cell cycle progression at G2/M (By similarity). [CWC2_YEAST] Involved in the first step of pre-mRNA splicing. Required for cell growth and cell cycle control. Plays a role in the levels of the U1, U4, U5 and U6 snRNAs and the maintenance of the U4/U6 snRNA complex. May provide the link between the "nineteen complex" NTC spliceosome protein complex and the spliceosome through the U6 snRNA. Associates predominantly with U6 snRNAs in assembled active spliceosomes. Binds directly to the internal stem-loop (ISL) domain of the U6 snRNA and to the pre-mRNA intron near the 5' splice site during the activation and catalytic phases of the spliceosome cycle. Binds also to U1, U4, U5 and U6 snRNAs and to pre-mRNAs, in vitro. Is not required for the Prp2-mediated remodeling of the activated spliceosome. [CEF1_YEAST] Involved in pre-mRNA splicing and cell cycle control. Required for the binding of the NTC complex (or PRP19-associated complex) components to the spliceosome to mediate conformational rearrangement or to stabilize the structure of the spliceosome after U4 snRNA dissociation, which leads to spliceosome maturation. Its absence leads to an arrest of the cell cycle, possibly due to the inefficient splicing of TUB1. [CWC15_YEAST] Involved in pre-mRNA splicing. [SLU7_YEAST] Essential protein involved in the second catalytic step of pre-mRNA splicing. Involved in the selection of 3'-type splice sites; this selection could be done via a 3'-splice site-binding factor, PRP16. [CWC22_YEAST] May be involved in pre-mRNA splicing. [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. [PRP45_YEAST] Involved in pre-mRNA splicing. Associated with the spliceosome throughout the splicing reactions, until after the second catalytic step. [PRP18_YEAST] Component of the U4/U5/U6 snRNP, binding principally to the u5 snRNP. It is not absolutely required for the second step of pre-mRNA splicing at low temperatures but is required at higher temperatures. It may stabilize a particular conformation of the U5 snRNP or orient the U5 snRNP within the U4/U5/U6 snRNP or within the spliceosome. Publication Abstract from PubMed The spliceosome excises introns from pre-mRNAs in two sequential trans-esterifications - branching and exon ligation1 - catalysed at a single catalytic metal site in U6 snRNA2,3. The recent structures of the spliceosomal C complex4,5 with the cleaved 5'-exon and lariat-3'-exon bound to the catalytic centre revealed that branching-specific factors such as Cwc25 lock the branch helix into position for nucleophilic attack of the branch adenosine at the 5'-splice site. Furthermore, the ATPase Prp16 is positioned to bind and translocate the intron downstream of the branch point to destabilize branching-specific factors and release the branch helix from the active site4. Here we present the 3.8 A cryo-electron microscopy structure of a Saccharomyces cerevisiae spliceosome stalled after Prp16-mediated remodelling but prior to exon ligation. While the U6 snRNA catalytic core remains firmly held in the active site cavity of Prp8 by proteins common to both steps, the branch helix has rotated by 75 degrees compared to complex C and is stabilized into a new position by Prp17, Cef1, and the reoriented Prp8 RNaseH domain. This rotation of the branch helix removes the branch adenosine from the catalytic core, creates a space for 3'-exon docking, and restructures the pairing of the 5'-splice site with the U6 snRNA ACAGAGA region. Slu7 and Prp18, which promote exon ligation, bind together to the Prp8 RNaseH domain. The ATPase Prp22, bound to Prp8 in place of Prp16, could interact with the 3'-exon, suggesting a possible basis for mRNA release after exon ligation6,7. Together with the C complex structure4, our new C* complex structure reveals the two major conformations of the spliceosome during the catalytic stages of splicing. Structure of a spliceosome remodelled for exon ligation.,Fica SM, Oubridge C, Galej WP, Wilkinson ME, Bai XC, Newman AJ, Nagai K Nature. 2017 Jan 11. doi: 10.1038/nature21078. PMID:28076345 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Pre-mRNA splicing factors 3D structures

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