View source for 5hci


==GPN-loop GTPase Npa3 in complex with GDP==
<StructureSection load='5hci' size='340' side='right'caption='[[5hci]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5hci]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5HCI OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5HCI FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GDP:GUANOSINE-5-DIPHOSPHATE'>GDP</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</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=5hci FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5hci OCA], [https://pdbe.org/5hci PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5hci RCSB], [https://www.ebi.ac.uk/pdbsum/5hci PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5hci ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/GPN1_YEAST GPN1_YEAST] Small GTPase required for proper nuclear import of RNA polymerase II (RNAPII) (PubMed:20855544, PubMed:21844196). May act at an RNAP assembly step prior to nuclear import (PubMed:23267056). Promotes sister chromatid separation during anaphase (PubMed:21532343).<ref>PMID:15082539</ref> <ref>PMID:20855544</ref> <ref>PMID:21532343</ref> <ref>PMID:21844196</ref> <ref>PMID:23267056</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Biogenesis of the 12-subunit RNA polymerase II (Pol II) transcription complex requires so-called GPN-loop GTPases, but the function of these enzymes is unknown. Here we report the first crystal structure of a eukaryotic GPN-loop GTPase, the S. cerevisiae enzyme Npa3 (a homolog of human GPN1, also called RPAP4, XAB1, MBDin), and analyze its catalytic mechanism. The enzyme was trapped in a GDP-bound, closed conformation, and in a novel GTP analogue-bound, open conformation displaying a conserved hydrophobic pocket distant from the active site. We show that Npa3 has chaperone activity and interacts with hydrophobic peptide regions of Pol II subunits that form interfaces in the assembled Pol II complex. Biochemical results are consistent with a model that the hydrophobic pocket binds peptides, and that this can allosterically stimulate GTPase activity and subsequent peptide release. These results suggest that GPN-loop GTPases are assembly chaperones for Pol II and other protein complexes.

Structure of GPN-loop GTPase Npa3 and implications for RNA polymerase II assembly.,Niesser J, Wagner FR, Kostrewa D, Muhlbacher W, Cramer P Mol Cell Biol. 2015 Dec 28. pii: MCB.01009-15. PMID:26711263<ref>PMID:26711263</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5hci" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Saccharomyces cerevisiae]]
[[Category: Cramer P]]
[[Category: Kostrewa D]]
[[Category: Muehlbacher W]]
[[Category: Niesser J]]
[[Category: Wagner FR]]