phosphoacceptor receiver (REC) domain of Spo0F and similar domains
Spo0F, a stand-alone response regulator containing only a REC domain with no output/effector domain, controls sporulation in Bacillus subtilis through the exchange of a phosphoryl group. Bacillus subtilis forms spores when conditions for growth become unfavorable. The initiation of sporulation is controlled by a phosphorelay (an expanded version of the two-component system) that consists of four main components: a histidine kinase (KinA), a secondary messenger (Spo0F), a phosphotransferase (Spo0B), and a transcription factor (Spo0A). REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.
Comment:also based on metal binding site of other family members
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.",