6CT9 | pdb_00006ct9

Structure of the human cGAS-DNA complex

• PDB DOI: https://doi.org/10.2210/pdb6CT9/pdb
• NAKB: 6CT9

• Classification: TRANSFERASE/DNA
• Organism(s): Homo sapiens, synthetic construct
• Expression System: Escherichia coli
• Mutation(s): Yes 


• Deposited: 2018-03-22 Released: 2018-07-18 
• Deposition Author(s): Zhou, W., Whiteley, A.T., de Oliveira Mann, C.C., Morehouse, B.R., Mekalanos, J.J., Kranzusch, P.J.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.26 Å
• R-Value Free: 
  0.228 (Depositor), 0.230 (DCC) 
• R-Value Work: 
  0.199 (Depositor), 0.202 (DCC) 
• R-Value Observed: 
  0.202 (Depositor) 

Starting Model: experimental

Literature

Structure of the Human cGAS-DNA Complex Reveals Enhanced Control of Immune Surveillance.

Zhou, W., Whiteley, A.T., de Oliveira Mann, C.C., Morehouse, B.R., Nowak, R.P., Fischer, E.S., Gray, N.S., Mekalanos, J.J., Kranzusch, P.J.

(2018) Cell 174: 300-311.e11

• PubMed: 30007416 
• DOI: https://doi.org/10.1016/j.cell.2018.06.026
• Primary Citation Related Structures: 
  6CT9, 6CTA


• PubMed Abstract: 
  

  Cyclic GMP-AMP synthase (cGAS) recognition of cytosolic DNA is critical for immune responses to pathogen replication, cellular stress, and cancer. Existing structures of the mouse cGAS-DNA complex provide a model for enzyme activation but do not explain why human cGAS exhibits severely reduced levels of cyclic GMP-AMP (cGAMP) synthesis compared to other mammals. Here, we discover that enhanced DNA-length specificity restrains human cGAS activation. Using reconstitution of cGAMP signaling in bacteria, we mapped the determinant of human cGAS regulation to two amino acid substitutions in the DNA-binding surface. Human-specific substitutions are necessary and sufficient to direct preferential detection of long DNA. Crystal structures reveal why removal of human substitutions relaxes DNA-length specificity and explain how human-specific DNA interactions favor cGAS oligomerization. These results define how DNA-sensing in humans adapted for enhanced specificity and provide a model of the active human cGAS-DNA complex to enable structure-guided design of cGAS therapeutics.

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Organizational Affiliation: 
• Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA.
Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02115, USA. Electronic address: [e-mail].

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content 

• Total Structure Weight: 53.35 kDa 
• Atom Count: 3,555 
• Modeled Residue Count: 377 
• Deposited Residue Count: 401 
• Unique protein chains: 1
• Unique nucleic acid chains: 2

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Cyclic GMP-AMP synthase	A	367	Homo sapiens	Mutation(s): 2  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 GTEx:  ENSG00000164430

Entity ID: 2
Molecule	Chains	Length	Organism	Image
DNA (5'-D(P*CP*GP*TP*CP*TP*TP*CP*GP*GP*CP*AP*AP*T)-3')	B	17	synthetic construct

Entity ID: 3
Molecule	Chains	Length	Organism	Image
DNA (5'-D(*AP*AP*AP*TP*TP*GP*CP*CP*GP*AP*AP*GP*AP*CP*GP*A)-3')	C	17	synthetic construct

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
ZN	D [auth A]	ZINC ION Zn PTFCDOFLOPIGGS-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.26 Å
• R-Value Free:  0.228 (Depositor), 0.230 (DCC) 
• R-Value Work:  0.199 (Depositor), 0.202 (DCC) 
• R-Value Observed: 0.202 (Depositor) 

Space Group: P 6₁ 2 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 99.782	α = 90
b = 99.782	β = 90
c = 236.769	γ = 120

Software Package:

Software Name	Purpose
PHENIX	refinement
XDS	data reduction
Aimless	data scaling
PHASER	phasing

Structure Validation

Entry History 

Deposition Data

• Released Date: 2018-07-18 
Deposition Author(s): Zhou, W., Whiteley, A.T., de Oliveira Mann, C.C., Morehouse, B.R., Mekalanos, J.J., Kranzusch, P.J.

Revision History  

• Version 1.0: 2018-07-18
  Type: Initial release
  
• Version 1.1: 2018-08-01
  Changes: Data collection, Database references
• Version 1.2: 2019-04-17
  Changes: Author supporting evidence, Data collection
• Version 1.3: 2023-10-04
  Changes: Data collection, Database references, Refinement description