View source for 1rkl


==NMR structure of yeast oligosaccharyltransferase subunit Ost4p==
<StructureSection load='1rkl' size='340' side='right'caption='[[1rkl]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1rkl]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Saccharomyces_cerevisiae_S288C Saccharomyces cerevisiae S288C]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RKL OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1RKL FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</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=1rkl FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1rkl OCA], [https://pdbe.org/1rkl PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1rkl RCSB], [https://www.ebi.ac.uk/pdbsum/1rkl PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1rkl ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/OST4_YEAST OST4_YEAST] Essential subunit of the N-oligosaccharyl transferase (OST) complex which catalyzes the transfer of a high mannose oligosaccharide from a lipid-linked oligosaccharide donor to an asparagine residue within an Asn-X-Ser/Thr consensus motif in nascent polypeptide chains. N-glycosylation occurs cotranslationally and the complex associates with the Sec61 complex at the channel-forming translocon complex that mediates protein translocation across the endoplasmic reticulum (ER). All subunits are required for a maximal enzyme activity. OST4 is required for recruitment of OST3 or OST6 to the OST complex. It is essential for cell growth at 37 but not at 25 degrees Celsius.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
N-glycosylation of proteins is an essential, highly conserved modification reaction that occurs in all eukaryotes and some prokaryotes. This process is catalyzed by oligosaccharyltransferase (OT), a multisubunit enzyme localized in the endoplasmic reticulum. Complete loss of N-glycosylation is lethal in all organisms. In Saccharomyces cerevisiae, OT is composed of nine nonidentical membrane proteins. Here, we report the atomic structure of an OT subunit from S. cerevisiae, Ost4p. This unusually small membrane protein containing only 36 residues folds into a well formed, kinked helix in the model-membrane solvent system used in this study. The residues critical for the OT activity and the stability of Stt3p-Ost4p-Ost3p subcomplex are located in helix alpha2, the larger cytosolic half of this kinked helix. The residues known to disrupt Ost4p-Stt3p complex form a well defined ridge in the 3D structure. Taking together prior mutational studies and the NMR structure of Ost4p, we propose that in the OT complex Stt3p is packed against the alpha 2-helix of Ost4p by using a "ridges-into-grooves" model, with Met-18, Leu-21, and Ile-24 as the packing interface on one face, whereas Ost3p is involved in interactions with Met-19, Thr-20, Ile-22, and Val-23 on the other face.

Structural basis for the function of a minimembrane protein subunit of yeast oligosaccharyltransferase.,Zubkov S, Lennarz WJ, Mohanty S Proc Natl Acad Sci U S A. 2004 Mar 16;101(11):3821-6. Epub 2004 Mar 4. PMID:15001703<ref>PMID:15001703</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 1rkl" style="background-color:#fffaf0;"></div>

==See Also==
*[[Glycosyltransferase 3D structures|Glycosyltransferase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Saccharomyces cerevisiae S288C]]
[[Category: Lennarz WJ]]
[[Category: Mohanty S]]
[[Category: Zubkov S]]