Predicted sensor/effector coupled domain which occurs in conserved genome contexts with the SMODS nucleotide synthetase. In addition to the predicted pore-forming 2TM region, the domain contains seven predicted beta-strands, suggestive of a lipocalin-like beta-barrel structure which could act as the sensor which activates the pore-forming effector response [1].

1: Comparative genomic analyses reveal a vast, novel network of nucleotide-centric systems in biological conflicts, immunity and signaling. Burroughs AM, Zhang D, Schaffer DE, Iyer LM, Aravind L; Nucleic Acids Res. 2015;43:10633-10654. PMID:26590262