<p>This entry represents a domain within bacterial and archaeal proteins, most of which are hypothetical. More than one copy is sometimes found in each protein in this entry. These include KaiC, which is one of the Kai proteins among which direct protein-protein association may be a critical process in the generation of circadian rhythms in cyanobacteria [<cite idref="PUB00012817"/>].</p><p> The circadian clock protein KaiC, is encoded in the kaiABC operon that controls circadian rhythms and may be universal inCyanobacteria. Each member contains two copies of this domain, which is also found in other proteins. KaiC performs autophosphorylation and acts as its own transcriptional repressor.</p><p>RadA/Sms is a highly conserved eubacterial protein that shares sequence similarity with both RecA strand transferase and lon protease. The RadA/Sms family are probable ATP-dependent proteases involved in both DNA repair and degradation of proteins, peptides, glycopeptides. They are classified in as non-peptidase homologues and unassigned peptidases in MEROPS peptidase family S16 (lon protease family, clan SJ).</p><p>RadA/Sms is involved in recombination and recombinational repair, most likely involving the stabilisation or processing of branched DNA molecules or blocked replication forks because of its genetic redundancy with RecG and RuvABC [<cite idref="PUB00011878"/>].</p> Circadian clock protein KaiC/DNA repair protein RadA