phosphoacceptor receiver (REC) domain of EcPhoP-like OmpR family response regulators
Escherichia coli PhoP (EcPhoP) is part of the PhoQ/PhoP two-component system (TCS) that regulates virulence genes and plays an essential role in the response of the bacteria to the environment of their mammalian hosts, sensing several stimuli such as extracellular magnesium limitation, low pH, the presence of cationic antimicrobial peptides, and osmotic upshift. This subfamily also includes Brucella suis FeuP, part of the FeuPQ TCS that is involved in the regulation of iron uptake, and Microchaete diplosiphon RcaC, which is required for chromatic adaptation. Members of this subfamily belong to the OmpR family of DNA-binding response regulators, which contain N-terminal receiver (REC) and C-terminal DNA-binding winged helix-turn-helix effector domains. REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.
Comment:signal transduction in two-component systems is mediated by metal ion dependent phosphorelay reactions between protein histidine kinases and phosphoaccepting receiver domains in response regulator proteins
Comment:for many receivers, Mg2+ is the preferred metal ion, but other divalent ions such as Mn2+ are also used
Jiyao W et al.(2023). "The conserved domain database in 2023.",