View source for 6lrk


==Human cGAS catalytic domain bound with compound 40==
<StructureSection load='6lrk' size='340' side='right'caption='[[6lrk]], [[Resolution|resolution]] 2.25&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6lrk]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6LRK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6LRK FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ER6:(3R)-1-pyrrolo[1,2-a]quinoxalin-4-ylpiperidine-3-carboxylic+acid'>ER6</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">CGAS, C6orf150, MB21D1 ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Cyclic_GMP-AMP_synthase Cyclic GMP-AMP synthase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.86 2.7.7.86] </span></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=6lrk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6lrk OCA], [https://pdbe.org/6lrk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6lrk RCSB], [https://www.ebi.ac.uk/pdbsum/6lrk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6lrk ProSAT]</span></td></tr>
</table>
== Function ==
[[https://www.uniprot.org/uniprot/CGAS_HUMAN CGAS_HUMAN]] Nucleotidyltransferase that catalyzes formation of cyclic GMP-AMP (cGAMP) from ATP and GTP and exhibits antiviral activity. Has antiviral activity by acting as a key cytosolic DNA sensor, the presence of DNA in the cytoplasm being a danger signal that triggers the immune responses. Binds cytosolic DNA directly, leading to activation and synthesis of cGAMP, a second messenger that binds to and activates TMEM173/STING, thereby triggering type-I interferon production.<ref>PMID:21478870</ref> <ref>PMID:23258413</ref>  
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Cyclic GMP-AMP synthase (cGAS) has been recently uncovered to be a promising therapeutic target for immune-associated diseases. Until now, only a few inhibitors have been identified through high-throughput screening campaigns. Here, we reported the discovery of novel inhibitors for the catalytic domain of human cGAS (h-cGAS(CD)) by virtual screening for the first time. To generate a reliable docking mode, we first obtained a high-resolution crystal structure of h-cGAS(CD) in complex with PF-06928215, a known inhibitor of h-cGAS, followed by molecular dynamics simulations on this complex structure. Four fragment hits were identified by the virtual screening together with a thermal shift assay. The crystal structures of these four compounds in complex with h-cGAS(CD) were subsequently determined, and the binding modes of the compounds were similar to those predicted by molecular docking, supporting the reliability of the docking model. In addition, an enzyme activity assay identified compound 18 (IC50 = 29.88 +/- 3.20 muM) from the compounds predicted by the virtual screening. A similarity search of compound 18 followed by a second virtual screening led to the discovery of compounds S2 (IC50 = 13.1 +/- 0.09 muM) and S3 (IC50 = 4.9 +/- 0.26 muM) as h-cGAS inhibitors with improved potency. Therefore, the present study not only provides the validated hit compounds for further development of h-cGAS inhibitors but also demonstrates a cross-validation study of virtual screening, in vitro experimental assays, and crystal structure determination.

In Silico Screening-Based Discovery of Novel Inhibitors of Human Cyclic GMP-AMP Synthase: A Cross-Validation Study of Molecular Docking and Experimental Testing.,Zhao W, Xiong M, Yuan X, Li M, Sun H, Xu Y J Chem Inf Model. 2020 Jun 22;60(6):3265-3276. doi: 10.1021/acs.jcim.0c00171., Epub 2020 Jun 9. PMID:32459092<ref>PMID:32459092</ref>

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

==See Also==
*[[Cyclic GMP-AMP synthase 3D synthase|Cyclic GMP-AMP synthase 3D synthase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Cyclic GMP-AMP synthase]]
[[Category: Human]]
[[Category: Large Structures]]
[[Category: Sun, H B]]
[[Category: Xiong, M Y]]
[[Category: Xu, Y C]]
[[Category: Yuan, X J]]
[[Category: Zhao, W F]]
[[Category: Cga]]
[[Category: Complex structure]]
[[Category: Dna binding protein]]
[[Category: Inhibitor]]