DNA-DNA contacts in vivo by bridging matS sites. However, although MatP connected distant sites in Hi-C studies, it did not specifically connect the matS sites. Furthermore, a MatP mutant that was unable to form tetramers behaved like wild-type. These results argue against the matS bridging model for Ter organization, leaving the mechanism of MatP action elusive. One possibility is that MatP spreads to nearby DNA segments from its primary matS binding site and bridge distant sites via a mechanism that does not depend on the tetramerization. MukBEF MukB belongs to a family of ATPases called structural maintenance of chromosome proteins (SMCs), which participate in higher-order chromosome organization in eukaryotes. Two MukB monomers associate via continuous antiparallel coiled-coil interaction forming a 100-nm long rigid rod. A flexible hinge region occurs in the middle of the rod. Due to the flexibility of the hinge region, MukB adopts a characteristic V-shape of the SMC family. The non-SMC subunits associating with MukB are MukE and MukF. The association closes the V formation, resulting in large ring-like structures. MukE and MukF are encoded together with MukB in the same operon in E. coli. Deletion of either subunit results in the same phenotype suggesting that the MukBEF complex is the functional unit in vivo. DNA binding activities of the complex reside in the MukB subunit, whereas MukE and MukF modulate MukB activity. MukBEF complex, together with Topo IV, is required for decatenation and repositioning of newly replicated oriCs. The role of MukBEF is not restricted during DNA replication. It organizes and condenses DNA even in non-replicating cells. The recent high-resolution chromosome conformation map of the MukB-depleted E. coli strain reveals that MukB participates in the formation of DNA-DNA interactions on the entire chromosome, except in the Ter domain. How is MukB prevented from acting in the Ter domain? MatP physically interacts with MukB, thus preventing MukB from localizing to the Ter domain. This is evident in the DNA binding of MatP and MukB in the Ter domain. DNA binding of MatP is enriched in the Ter domain, whereas DNA binding of MukB is reduced compared to the rest of the genome. Furthermore, in a strain already lacking MatP, the absence of MukB causes a reduction in DNA contacts throughout the chromosome, including the Ter domain. This result agrees with the view that MatP displaces MukB from the Ter domain. How does the MukBEF complex function to