A predicted toxin of the HNH/Endonuclease VII fold present in bacterial polymorphic toxin systems with a characteristic sG[HQ]H signature motif. In bacterial polymorphic toxin systems, the toxin is exported by the type 2, type 6, type 7 or TcdB/TcaC-type secretion system. The metazoan teneurin proteins possess an inactive of this domain at their C-terminus [1].

1: Polymorphic toxin systems: comprehensive characterization of trafficking modes, processing, mechanisms of action, immunity and ecology using comparative genomics. Zhang D, de Souza RF, Anantharaman V, Iyer LM, Aravind L; Biol Direct. 2012;7:18. PMID:22731697