Chromosome-partitioning protein ParB

UniProtKB accession:  Q1CVJ4

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UniProtKB description:  An essential component of the chromosome segregation machinery (PubMed:24466283). The ParABS system segregates newly replicated chromosomes during bacterial cell division. After DNA replication the ParB-parS partition complexes interact with ParA ATPase, promoting the movement of the origin region towards opposite cell poles (Probable). Binds DNA close to the origin of replication (the parS cluster) (PubMed:24466283). parS sequences (but not a mutated parS sequence) stimulate CTP hydrolysis by ParB (PubMed:31835030, PubMed:34562373). Upon DNA and CTP binding forms a closed sliding rings that spread one-dimensionally over about 33 kb of DNA centered on the parS cluster (PubMed:34562373). CTP hydrolysis opens the ring, allowing DNA release and dissociation of ParB (PubMed:34562373). CTP hydrolysis appears to serve as a timing mechanism for ParB sliding rings; slower hydrolysis leads to larger ring spreading (PubMed:34562373). ParB dimers are dynamic and exchange rapidly in the cell (PubMed:34562373). Mutants that have decreased CTPase activity accumulate over a greater spread of DNA and form abnormal cellular foci (PubMed:34562373). Does not hydrolyze ATP, GTP or UTP (PubMed:31835030). Binds CTP via its ParB/Srx domain (PubMed:31835030, PubMed:34562373). Required for Smc to stably accumulate (PubMed:32738827).