7UQ2

Vs.4 from T4 phage in complex with cGAMP

Summary for 7UQ2

• Entry DOI: 10.2210/pdb7uq2/pdb
• Descriptor: Vs.4, 2-amino-9-[(2R,3R,3aS,5R,7aR,9R,10R,10aS,12R,14aR)-9-(6-amino-9H-purin-9-yl)-3,5,10,12-tetrahydroxy-5,12-dioxidooctahydro-2H,7H-difuro[3,2-d:3',2'-j][1,3,7,9,2,8]tetraoxadiphosphacyclododecin-2-yl]-1,9-dihydro-6H-purin-6-one, CALCIUM ION, ... (4 entities in total)
• Functional Keywords: binds 3', 3'-cgamp, viral protein
• Biological source: Tequatrovirus
• Total number of polymer chains: 6
• Total formula weight: 64047.58

Authors

Jenson, J.M.,Chen, Z.J. (deposition date: 2022-04-18, release date: 2023-02-08, Last modification date: 2024-10-23)

Primary citation

Jenson, J.M.,Li, T.,Du, F.,Ea, C.K.,Chen, Z.J.
Ubiquitin-like conjugation by bacterial cGAS enhances anti-phage defence.
Nature, 616:326-331, 2023

PubMed Abstract: cGAS is an evolutionarily conserved enzyme that has a pivotal role in immune defence against infection. In vertebrate animals, cGAS is activated by DNA to produce cyclic GMP-AMP (cGAMP), which leads to the expression of antimicrobial genes. In bacteria, cyclic dinucleotide (CDN)-based anti-phage signalling systems (CBASS) have been discovered. These systems are composed of cGAS-like enzymes and various effector proteins that kill bacteria on phage infection, thereby stopping phage spread. Of the CBASS systems reported, approximately 39% contain Cap2 and Cap3, which encode proteins with homology to ubiquitin conjugating (E1/E2) and deconjugating enzymes, respectively. Although these proteins are required to prevent infection of some bacteriophages, the mechanism by which the enzymatic activities exert an anti-phage effect is unknown. Here we show that Cap2 forms a thioester bond with the C-terminal glycine of cGAS and promotes conjugation of cGAS to target proteins in a process that resembles ubiquitin conjugation. The covalent conjugation of cGAS increases the production of cGAMP. Using a genetic screen, we found that the phage protein Vs.4 antagonized cGAS signalling by binding tightly to cGAMP (dissociation constant of approximately 30 nM) and sequestering it. A crystal structure of Vs.4 bound to cGAMP showed that Vs.4 formed a hexamer that was bound to three molecules of cGAMP. These results reveal a ubiquitin-like conjugation mechanism that regulates cGAS activity in bacteria and illustrates an arms race between bacteria and viruses through controlling CDN levels.

PubMed: 36848932
DOI: 10.1038/s41586-023-05862-7

Experimental method

X-RAY DIFFRACTION (2 Å)