CHASE3 is an extracellular sensory domain, which is present in various classes of transmembrane receptors that are parts of signal transduction pathways in bacteria. Specifically, CHASE3 domains are found in histidine kinases, adenylate cyclases, methyl-accepting chemotaxis proteins and predicted diguanylate cyclases/phosphodiesterases [1]. This domain recognises pyrene (Matilla et al., FEMS Microbiology Reviews, fuab043, 45, 2021, 1. https://doi.org/10.1093/femsre/fuab043).

1: Common extracellular sensory domains in transmembrane receptors for diverse signal transduction pathways in bacteria and archaea. Zhulin IB, Nikolskaya AN, Galperin MY; J Bacteriol 2003;185:285-294. PMID:12486065