View source for 6ahd


==The Cryo-EM Structure of Human Pre-catalytic Spliceosome (B complex) at 3.8 angstrom resolution==
<SX load='6ahd' size='340' side='right' viewer='molstar' caption='[[6ahd]], [[Resolution|resolution]] 3.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6ahd]] is a 12 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6AHD OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6AHD FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GTP:GUANOSINE-5-TRIPHOSPHATE'>GTP</scene>, <scene name='pdbligand=IHP:INOSITOL+HEXAKISPHOSPHATE'>IHP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=6ahd FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6ahd OCA], [https://pdbe.org/6ahd PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6ahd RCSB], [https://www.ebi.ac.uk/pdbsum/6ahd PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6ahd ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/SMD3_HUMAN 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.<ref>PMID:11574479</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The pre-catalytic spliceosome (B complex) is preceded by its precursor spliceosome (pre-B complex) and followed by the activated spliceosome (B(act) complex). The pre-B-to-B and B-to-B(act) transitions are driven by the ATPase/helicases Prp28 and Brr2, respectively. In this study, we report the cryo-electron microscopy structures of the human pre-B complex and the human B complex at an average resolution of 5.7 and 3.8 A, respectively. In the pre-B complex, U1 and U2 small nuclear ribonucleoproteins (snRNPs) associate with two edges of the tetrahedron-shaped U4/U6.U5 tri-snRNP. The pre-mRNA is yet to be recognized by U5 or U6 small nuclear RNA (snRNA), and loop I of U5 snRNA remains unengaged. In the B complex, U1 snRNP and Prp28 are dissociated, the 5'-exon is anchored to loop I of U5 snRNA, and the 5'-splice site is recognized by U6 snRNA through duplex formation. In sharp contrast to S. cerevisiae, most components of U2 snRNP and tri-snRNP, exemplified by Brr2, undergo pronounced rearrangements in the human pre-B-to-B transition. Structural analysis reveals mechanistic insights into the assembly and activation of the human spliceosome.

Structures of the human pre-catalytic spliceosome and its precursor spliceosome.,Zhan X, Yan C, Zhang X, Lei J, Shi Y Cell Res. 2018 Oct 12. pii: 10.1038/s41422-018-0094-7. doi:, 10.1038/s41422-018-0094-7. PMID:30315277<ref>PMID:30315277</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6ahd" style="background-color:#fffaf0;"></div>

==See Also==
*[[Pre-mRNA splicing factors 3D structures|Pre-mRNA splicing factors 3D structures]]
*[[Sm-like protein 3D structures|Sm-like protein 3D structures]]
*[[U5-15kD|U5-15kD]]
== References ==
<references/>
__TOC__
</SX>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Shi Y]]
[[Category: Yan C]]
[[Category: Zhan X]]
[[Category: Zhang X]]