6CT9 image
Entry Detail
PDB ID:
6CT9
Keywords:
TRANSFERASE/DNA
Title:
Structure of the human cGAS-DNA complex
Biological Source:
Source Organism:
Homo sapiens, synthetic construct
Host Organism:
Escherichia coli
PDB Version:
Deposition Date:
2018-03-22
Release Date:
2018-07-18
Method Details:
Experimental Method:
X-RAY DIFFRACTION
Resolution:
2.26 Å
R-Value Free:
0.22
R-Value Work:
0.19
R-Value Observed:
0.20
Space Group:
P 61 2 2
6CT9 validation report
Macromolecular Entities
Protein Blast
Polymer Type:polypeptide(L)
Description:Cyclic GMP-AMP synthase
Mutations:K187N, L195R
Chain IDs:A
Chain Length:367
Number of Molecules:1
Biological Source:Homo sapiens
UniProt ID:Q8N884 Pfam ID:PF03281, PF20266 EC:2.7.7.86
Polymer Type:polydeoxyribonucleotide
Description:DNA (5'-D(P*CP*GP*TP*CP*TP*TP*CP*GP*GP*CP*AP*AP*T)-3')
Chain IDs:B
Chain Length:17
Number of Molecules:1
Biological Source:synthetic construct
Polymer Type:polydeoxyribonucleotide
Description:DNA (5'-D(*AP*AP*AP*TP*TP*GP*CP*CP*GP*AP*AP*GP*AP*CP*GP*A)-3')
Chain IDs:C
Chain Length:17
Number of Molecules:1
Biological Source:synthetic construct
Ligand Molecules
ZN
Primary Citation
Structure of the Human cGAS-DNA Complex Reveals Enhanced Control of Immune Surveillance.
Cell 174 300 311.e11 (2018)
PMID: 30007416 DOI: 10.1016/j.cell.2018.06.026

Abstact

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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Disease

Primary Citation of related structures
6CT9