This domain is associated to sensor histidine kinases and recognises citrate and TCA cycle intermediates, Ag(II), Zn(II), Mg(II) (Matilla et al., FEMS Microbiology Reviews, fuab043, 45, 2021, 1. https://doi.org/10.1093/femsre/fuab043).

1: Cache Domains That are Homologous to, but Different from PAS Domains Comprise the Largest Superfamily of Extracellular Sensors in Prokaryotes. Upadhyay AA, Fleetwood AD, Adebali O, Finn RD, Zhulin IB; PLoS Comput Biol. 2016;12:e1004862. PMID:27049771