This domain, previously known as DUF7681, is found in phage proteins including Anti-CBASS protein 2 (Acb2) and Thoeris anti-defense 1 (Tad1). It folds into an alpha-helical hairpin that is found either standalone (in Acb2) or in combination with a fo ...
This domain, previously known as DUF7681, is found in phage proteins including Anti-CBASS protein 2 (Acb2) and Thoeris anti-defense 1 (Tad1). It folds into an alpha-helical hairpin that is found either standalone (in Acb2) or in combination with a four-stranded antiparallel beta-sheet domain (in Tad1) [1,2,3]. Prokaryotic anti-phage immune systems use TIR and cGAS-like enzymes to produce 1-3-glycocyclic ADP-ribose; and cyclic dinucleotide and trinucleotide signalling molecules, respectively, which limit phage replication. The Thoeris anti-defence proteins Tad1 and Tad2 are both pronged inhibitors and antagonise immunity alongside Anti-CBASS protein 2. These proteins achieve anti-cyclic-oligonucleotide-based anti-phage signalling system (anti-CBASS) activity by sequestering a considerable amount of cyclic nucleotides. Each of these proteins is using distinct binding pockets. The residues conserved in Tad1 and Acb2 are located near these binding sites [3,4].
