View source for 6tka


==Crystal structure of human O-GlcNAc transferase bound to substrate 7 and a peptide from HCF-1 pro-repeat 2 (11-26)==
<StructureSection load='6tka' size='340' side='right'caption='[[6tka]], [[Resolution|resolution]] 1.91&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6tka]] is a 2 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=6TKA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6TKA 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]] 1.91&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NG8:3-[2,2-bis(fluoranyl)-10,12-dimethyl-1,3-diaza-2$l^{4}-boratricyclo[7.3.0.0^{3,7}]dodeca-4,6,9,11-tetraen-4-yl]-~{N}-ethyl-propanamide'>NG8</scene>, <scene name='pdbligand=NJ5:[[(2~{R},3~{S},4~{R},5~{R})-5-[2,4-bis(oxidanylidene)pyrimidin-1-yl]-3,4-bis(oxidanyl)oxolan-2-yl]methoxy-oxidanyl-phosphoryl]+[(2~{R},3~{R},4~{R},5~{S},6~{R})-3-[6-(butanoylamino)hexanoylamino]-6-(hydroxymethyl)-4,5-bis(oxidanyl)oxan-2-yl]+hydrogen+phosphate'>NJ5</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=6tka FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6tka OCA], [https://pdbe.org/6tka PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6tka RCSB], [https://www.ebi.ac.uk/pdbsum/6tka PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6tka ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/OGT1_HUMAN OGT1_HUMAN] Regulation of OGT activity and altered O-GlcNAcylations are implicated in diabetes and Alzheimer disease. O-GlcNAcylation of AKT1 affects insulin signaling and, possibly diabetes. Reduced O-GlcNAcylations and resulting increased phosphorylations of MAPT/TAU are observed in Alzheimer disease (AD) brain cerebrum.
== Function ==
[https://www.uniprot.org/uniprot/OGT1_HUMAN OGT1_HUMAN] Catalyzes the transfer of a single N-acetylglucosamine from UDP-GlcNAc to a serine or threonine residue in cytoplasmic and nuclear proteins resulting in their modification with a beta-linked N-acetylglucosamine (O-GlcNAc). Glycosylates a large and diverse number of proteins including histone H2B, AKT1, PFKL, KMT2E/MLL5, MAPT/TAU and HCFC1. Can regulate their cellular processes via cross-talk between glycosylation and phosphorylation or by affecting proteolytic processing. Involved in insulin resistance in muscle and adipocyte cells via glycosylating insulin signaling components and inhibiting the 'Thr-308' phosphorylation of AKT1, enhancing IRS1 phosphorylation and attenuating insulin signaling. Involved in glycolysis regulation by mediating glycosylation of 6-phosphofructokinase PFKL, inhibiting its activity. Component of a THAP1/THAP3-HCFC1-OGT complex that is required for the regulation of the transcriptional activity of RRM1. Plays a key role in chromatin structure by mediating O-GlcNAcylation of 'Ser-112' of histone H2B: recruited to CpG-rich transcription start sites of active genes via its interaction with TET proteins (TET1, TET2 or TET3). As part of the NSL complex indirectly involved in acetylation of nucleosomal histone H4 on several lysine residues.<ref>PMID:12150998</ref> <ref>PMID:18288188</ref> <ref>PMID:19451179</ref> <ref>PMID:19377461</ref> <ref>PMID:20018852</ref> <ref>PMID:20018868</ref> <ref>PMID:20200153</ref> <ref>PMID:20824293</ref> <ref>PMID:21285374</ref> <ref>PMID:22121020</ref> <ref>PMID:22923583</ref> <ref>PMID:23353889</ref> <ref>PMID:23222540</ref> <ref>PMID:15361863</ref> <ref>PMID:21240259</ref>   Isoform 2: the mitochondrial isoform (mOGT) is cytotoxic and triggers apoptosis in several cell types including INS1, an insulinoma cell line.<ref>PMID:12150998</ref> <ref>PMID:18288188</ref> <ref>PMID:19451179</ref> <ref>PMID:19377461</ref> <ref>PMID:20018852</ref> <ref>PMID:20018868</ref> <ref>PMID:20200153</ref> <ref>PMID:20824293</ref> <ref>PMID:21285374</ref> <ref>PMID:22121020</ref> <ref>PMID:22923583</ref> <ref>PMID:23353889</ref> <ref>PMID:23222540</ref> <ref>PMID:15361863</ref> <ref>PMID:21240259</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Glycosyltransferases carry out important cellular functions in species ranging from bacteria to humans. Despite their essential roles in biology, simple and robust activity assays that can be easily applied to high-throughput screening for inhibitors of these enzymes have been challenging to develop. Here we report a bead-based strategy to sensitively measure the group transfer activity of glycosyltransferases using simple fluorescence measurements, without the need for coupled enzymes or secondary reactions. We validate the performance and accuracy of the assay using O -GlcNAc Transferase (OGT) as a model system through detailed Michaelis-Menten kinetic analysis of various substrates and inhibitors. Optimization of this assay and application to high-throughput screening enabled screening for inhibitors of OGT, leading to a novel inhibitory scaffold. We believe this assay will prove valuable not only for the study of OGT, but also more widely as a general approach for the screening of glycosyltransferases and other group transfer enzymes.

A direct fluorescent activity assay for glycosyltransferases enables convenient high-throughput screening: Application to O-GlcNAc Transferase.,Vocadlo DJ, Alteen MG, Gros C, Meek R, Cardoso DA, Busmann J, Sangouard G, Deen MC, Tan HY, Shen DL, Russell CC, Davies GJ, Robinson PJ, McCluskey A Angew Chem Int Ed Engl. 2020 Feb 24. doi: 10.1002/anie.202000621. PMID:32092778<ref>PMID:32092778</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6tka" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Davies GJ]]
[[Category: Meek RW]]