Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 9-mer - A2B2C2D2E1 Pseudo Symmetry: Asymmetric - C1 
Pseudo Stoichiometry: Hetero 9-mer - A7B1C1 Local Symmetry: Cyclic - C2  (3D View)
Local Stoichiometry: Hetero 8-mer - A2B2C2D2 

Local Symmetry: Cyclic - C2  (3D View)
Local Stoichiometry: Hetero 8-mer - A2B2C2D2 

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: microscopy

Macromolecule Content

• Total Structure Weight: 217.94 kDa 
• Atom Count: 14,857 
• Modelled Residue Count: 1,395 
• Deposited Residue Count: 1,408 
• Unique protein chains: 5
• Unique nucleic acid chains: 2

 7CCQ

Structure of the 1:1 cGAS-nucleosome complex

• PDB DOI:  https://doi.org/10.2210/pdb7CCQ/pdb
• EM Map EMD-30339: EMDB EMDataResource

• Classification: STRUCTURAL PROTEIN/TRANSFERASE/DNA
• Organism(s): Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2020-06-17 Released: 2020-10-07 
• Deposition Author(s): Cao, D., Han, X., Fan, X., Xu, R.M., Zhang, X.
• Funding Organization(s): Ministry of Science and Technology (MoST, China), National Natural Science Foundation of China (NSFC), Chinese Academy of Sciences

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 3.80 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Literature

Structural basis for nucleosome-mediated inhibition of cGAS activity.

Cao, D., Han, X., Fan, X., Xu, R.M., Zhang, X.

(2020) Cell Res 30: 1088-1097

• PubMed: 33051594 
• DOI: https://doi.org/10.1038/s41422-020-00422-4
• Primary Citation of Related Structures:  
  7CCQ, 7CCR


• PubMed Abstract: 
  

Activation of cyclic GMP-AMP synthase (cGAS) through sensing cytosolic double stranded DNA (dsDNA) plays a pivotal role in innate immunity against exogenous infection as well as cellular regulation under stress. Aberrant activation of cGAS induced by self-DNA is related to autoimmune diseases. cGAS accumulates at chromosomes during mitosis or spontaneously in the nucleus. Binding of cGAS to the nucleosome competitively attenuates the dsDNA-mediated cGAS activation, but the molecular mechanism of the attenuation is still poorly understood. Here, we report two cryo-electron microscopy structures of cGAS-nucleosome complexes. The structures reveal that cGAS interacts with the nucleosome as a monomer, forming 1:1 and 2:2 complexes, respectively. cGAS contacts the nucleosomal acidic patch formed by the H2A-H2B heterodimer through the dsDNA-binding site B in both complexes, and could interact with the DNA from the other symmetrically placed nucleosome via the dsDNA-binding site C in the 2:2 complex. The bound nucleosome inhibits the activation of cGAS through blocking the interaction of cGAS with ligand dsDNA and disrupting cGAS dimerization. R236A or R255A mutation of cGAS impairs the binding between cGAS and the nucleosome, and largely relieves the nucleosome-mediated inhibition of cGAS activity. Our study provides structural insights into the inhibition of cGAS activity by the nucleosome, and advances the understanding of the mechanism by which hosts avoid the autoimmune attack caused by cGAS.

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Organizational Affiliation: 

Center for Biological Imaging, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China. [e-mail].

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Histone H3.1	A, E	98	Homo sapiens	Mutation(s): 0  Gene Names:  H3C1, H3FA, HIST1H3A, H3C2, H3FL, HIST1H3B, H3C3, H3FC HIST1H3C, H3C4, H3FB, HIST1H3D, H3C6, H3FD, HIST1H3E, H3C7, H3FI, HIST1H3F, H3C8, H3FH, HIST1H3G, H3C10, H3FK, HIST1H3H, H3C11, H3FF, HIST1H3I, H3C12, H3FJ, HIST1H3J
UniProt & NIH Common Fund Data Resources
Find proteins for P68431 (Homo sapiens) Explore P68431  Go to UniProtKB:  P68431
PHAROS:  P68431

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Histone H4	B, F	80	Homo sapiens	Mutation(s): 0  Gene Names:  H4C1, H4/A, H4FA, HIST1H4A, H4C2, H4/I, H4FI, HIST1H4B, H4C3, H4/G, H4FG, HIST1H4C, H4C4, H4/B, H4FB, HIST1H4D, H4C5, H4/J, H4FJ, HIST1H4E, H4C6, H4/C, H4FC, HIST1H4F, H4C8, H4/H, H4FH, HIST1H4H, H4C9, H4/M, H4FM, HIST1H4I, H4C11, H4/E, H4FE, HIST1H4J, H4C12, H4/D, H4FD, HIST1H4K, H4C13, H4/K, H4FK, HIST1H4L, H4C14, H4/N, H4F2, H4FN, HIST2H4, HIST2H4A, H4C15, H4/O, H4FO, HIST2H4B, H4-16, HIST4H4
UniProt & NIH Common Fund Data Resources
Find proteins for P62805 (Homo sapiens) Explore P62805  Go to UniProtKB:  P62805
PHAROS:  P62805

Entity ID: 3
Molecule	Chains	Sequence Length	Organism	Details	Image
Histone H2A type 1-B/E	C, G	103	Homo sapiens	Mutation(s): 0  Gene Names: H2AC4, H2AFM, HIST1H2AB, H2AC8, H2AFA, HIST1H2AE
UniProt & NIH Common Fund Data Resources
Find proteins for P04908 (Homo sapiens) Explore P04908  Go to UniProtKB:  P04908
PHAROS:  P04908

Entity ID: 4
Molecule	Chains	Sequence Length	Organism	Details	Image
Histone H2B type 1-J	D, H	93	Homo sapiens	Mutation(s): 0  Gene Names: H2BC11, H2BFR, HIST1H2BJ
UniProt & NIH Common Fund Data Resources
Find proteins for P06899 (Homo sapiens) Explore P06899  Go to UniProtKB:  P06899
PHAROS:  P06899

Entity ID: 5
Molecule	Chains	Sequence Length	Organism	Details	Image
Cyclic GMP-AMP synthase	I [auth K]	366	Homo sapiens	Mutation(s): 0  Gene Names: CGAS, C6orf150, MB21D1 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

Entity ID: 6
Molecule	Chains	Length	Organism	Image
DNA (147-MER)	J [auth I]	147	Homo sapiens

Entity ID: 7
Molecule	Chains	Length	Organism	Image
DNA (147-MER)	K [auth J]	147	Homo sapiens

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 3.80 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2020-10-07 
Deposition Author(s): Cao, D., Han, X., Fan, X., Xu, R.M., Zhang, X.

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Funding Organization	Location	Grant Number
Ministry of Science and Technology (MoST, China)	China	2017YFA0504700
Ministry of Science and Technology (MoST, China)	China	2019YFA0508900
National Natural Science Foundation of China (NSFC)	China	31930069
National Natural Science Foundation of China (NSFC)	China	31521002
National Natural Science Foundation of China (NSFC)	China	31991162
Chinese Academy of Sciences	China	XDB37040101
Chinese Academy of Sciences	China	XDB37010101

Revision History  

• Version 1.0: 2020-10-07
  Type: Initial release
  
• Version 1.1: 2020-11-11
  Changes: Database references
• Version 1.2: 2020-12-23
  Changes: Database references