Structural highlights
Function
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.[1] [2]
Publication Abstract from PubMed
Cyclic GMP-AMP synthase (cGAS) plays an important role in the inflammatory response. It has been reported that aberrant activation of cGAS is associated with a variety of immune-mediated inflammatory disorders. The development of small molecule inhibitors of cGAS has been considered as a promising therapeutic strategy for the diseases. Flavonoids, a typical class of natural products, are known for their anti-inflammatory activities. Although cGAS is closely associated with inflammation, the potential effects of natural flavonoid compounds on cGAS have been rarely studied. Therefore, we screened an in-house natural flavonoid library by pyrophosphatase (PP(i)ase) coupling assay and identified novel cGAS inhibitors baicalein and baicalin. Subsequently, crystal structures of the two natural flavonoids in complex with human cGAS were determined, which provide mechanistic insight into the anti-inflammatory activities of baicalein and baicalin at the molecular level. After that, a virtual screening based on the crystal structures of baicalein and baicalin in complex with human cGAS was performed. As a result, compound C20 was identified to inhibit both human and mouse cGAS with IC(50) values of 2.28 and 1.44 muM, respectively, and its detailed interactions with human cGAS were further revealed by the X-ray crystal structure determination. These results demonstrate the potential of natural products used as hits in drug discovery and provide valuable hints for further development of cGAS inhibitors.
Discovery of novel cGAS inhibitors based on natural flavonoids.,Li J, Xiong M, Liu J, Zhang F, Li M, Zhao W, Xu Y Bioorg Chem. 2023 Nov;140:106802. doi: 10.1016/j.bioorg.2023.106802. Epub 2023 , Aug 22. PMID:37666112[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Schoggins JW, Wilson SJ, Panis M, Murphy MY, Jones CT, Bieniasz P, Rice CM. A diverse range of gene products are effectors of the type I interferon antiviral response. Nature. 2011 Apr 28;472(7344):481-5. doi: 10.1038/nature09907. Epub 2011 Apr 10. PMID:21478870 doi:10.1038/nature09907
- ↑ Sun L, Wu J, Du F, Chen X, Chen ZJ. Cyclic GMP-AMP synthase is a cytosolic DNA sensor that activates the type I interferon pathway. Science. 2013 Feb 15;339(6121):786-91. doi: 10.1126/science.1232458. Epub 2012, Dec 20. PMID:23258413 doi:10.1126/science.1232458
- ↑ Li J, Xiong M, Liu J, Zhang F, Li M, Zhao W, Xu Y. Discovery of novel cGAS inhibitors based on natural flavonoids. Bioorg Chem. 2023 Nov;140:106802. PMID:37666112 doi:10.1016/j.bioorg.2023.106802