6EDC

hcGAS-16bp dsDNA complex

Summary for 6EDC

• Entry DOI: 10.2210/pdb6edc/pdb
• Descriptor: Cyclic GMP-AMP synthase, DNA (5'-D(*AP*AP*AP*TP*TP*GP*CP*CP*GP*AP*AP*GP*AP*CP*GP*AP*A)-3'), DNA (5'-D(*TP*TP*CP*GP*TP*CP*TP*TP*CP*GP*GP*CP*AP*AP*T)-3'), ... (4 entities in total)
• Functional Keywords: human cgas dna complex, transferase-dna complex, transferase/dna
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 3
• Total formula weight: 53151.22

Authors

Xie, W.,Lama, L.,Adura, C.,Glickman, J.F.,Tuschl, T.,Patel, D.J. (deposition date: 2018-08-09, release date: 2019-05-29, Last modification date: 2023-10-11)

Primary citation

Xie, W.,Lama, L.,Adura, C.,Tomita, D.,Glickman, J.F.,Tuschl, T.,Patel, D.J.
Human cGAS catalytic domain has an additional DNA-binding interface that enhances enzymatic activity and liquid-phase condensation.
Proc.Natl.Acad.Sci.USA, 116:11946-11955, 2019

PubMed Abstract: The cyclic GMP-AMP synthase (cGAS)-cGAMP-STING pathway plays a key role in innate immunity, with cGAS sensing both pathogenic and mislocalized DNA in the cytoplasm. Human cGAS (h-cGAS) constitutes an important drug target for control of antiinflammatory responses that can contribute to the onset of autoimmune diseases. Recent studies have established that the positively charged N-terminal segment of cGAS contributes to enhancement of cGAS enzymatic activity as a result of DNA-induced liquid-phase condensation. We have identified an additional cGAS-DNA interface (labeled site-C; CD, catalytic domain) in the crystal structure of a human SRY.cGAS-DNA complex, with mutations along this basic site-C cGAS interface disrupting liquid-phase condensation, as monitored by cGAMP formation, gel shift, spin-down, and turbidity assays, as well as time-lapse imaging of liquid droplet formation. We expand on an earlier ladder model of cGAS dimers bound to a pair of parallel-aligned DNAs to propose a multivalent interaction-mediated cluster model to account for DNA-mediated condensation involving both the N-terminal domain of cGAS and the site-C cGAS-DNA interface. We also report the crystal structure of the h-cGAS-DNA complex containing a triple mutant that disrupts the site-C interface, with this complex serving as a future platform for guiding cGAS inhibitor development at the DNA-bound h-cGAS level. Finally, we solved the structure of RU.521 bound in two alternate alignments to apo h-cGAS, thereby occupying more of the catalytic pocket and providing insights into further optimization of active-site-binding inhibitors.

PubMed: 31142647
DOI: 10.1073/pnas.1905013116

Experimental method

X-RAY DIFFRACTION (2.712 Å)