8IMF

Human cGAS catalytic domain bound with baicalein


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.230 

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Ligand Structure Quality Assessment 


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Literature

Discovery of novel cGAS inhibitors based on natural flavonoids.

Li, J.Xiong, M.Liu, J.Zhang, F.Li, M.Zhao, W.Xu, Y.

(2023) Bioorg Chem 140: 106802-106802

  • DOI: https://doi.org/10.1016/j.bioorg.2023.106802
  • Primary Citation of Related Structures:  
    8IME, 8IMF, 8IMG

  • PubMed Abstract: 

    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 μM, 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.


  • Organizational Affiliation

    School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China; State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cyclic GMP-AMP synthase
A, B
366Homo sapiensMutation(s): 0 
Gene Names: CGASC6orf150MB21D1
EC: 2.7.7.86
UniProt & NIH Common Fund Data Resources
Find proteins for Q8N884 (Homo sapiens)
Explore Q8N884 
Go to UniProtKB:  Q8N884
PHAROS:  Q8N884
GTEx:  ENSG00000164430 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8N884
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.230 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 213.367α = 90
b = 45.981β = 113.42
c = 87.183γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data scaling
HKL-2000data reduction
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Not funded--

Revision History  (Full details and data files)

  • Version 1.0: 2024-01-03
    Type: Initial release