Thoeris is a bacterial antiphage defense system, which consists of two genes, thsA and thsB, via NAD+ degradation [1-4]. ThsA has robust NAD+ cleavage activity and and a two-domain architecture containing a N-terminal NAD-binding domain (denoted as sirtuin-like or Macro) and C-terminal SLOG-like domain. In some instances, such as in B. amyloliquefaciens ThsA has an N-terminal transmembrane domain [1]. ThsB (also referred to as TIR1 and TIR2) is structurally similar to TIR domain proteins but without enzymatic activity. This domain is found at the C-terminal of ThsA proteins which adopts a Rossmann-like fold that binds NAD+/NAD+derivatives. It has been characterised as the SLOG-like domain which binds NAD+ derivatives such as ADPR molecules produced by ThsB, which drives an oligomeric state change in ThsA and activates the NADase activity (represented in Pfam:PF18185) [1,3]. This entry represents the NAD+-binding Macro domain from B. amyloliquefaciens [1,2].

1: Systematic discovery of antiphage defense systems in the microbial pangenome. Doron S, Melamed S, Ofir G, Leavitt A, Lopatina A, Keren M, Amitai G, Sorek R; Science. 2018; [Epub ahead of print] PMID:29371424

2: Structural and functional evidence of bacterial antiphage protection by Thoeris defense system via NAD(+) degradation. Ka D, Oh H, Park E, Kim JH, Bae E; Nat Commun. 2020;11:2816. PMID:32499527

3: Antiviral activity of bacterial TIR domains via immune signalling molecules. Ofir G, Herbst E, Baroz M, Cohen D, Millman A, Doron S, Tal N, Malheiro DBA, Malitsky S, Amitai G, Sorek R; Nature. 2021;600:116-120. PMID:34853457