Plays a central role in chromosome condensation, segregation and cell cycle progression. Functions as a homodimer, which is essential for chromosome partition. Involved in negative DNA supercoiling in vivo, and by this means organize and compact chromosomes. May achieve or facilitate chromosome segregation by condensation DNA from both sides of a centrally located replisome during cell division. Homodimerization via its hinge domain. Binds to DNA via its C-terminal region. Interacts, and probably forms a ternary complex, with MukE and MukF via its C-terminal region. The complex formation is stimulated by calcium or magnesium. Interacts with tubulin-related protein FtsZ. Restricted to the nucleoid region. The hinge domain, which separates the large intramolecular coiled coil regions, allows the homodimerization, forming a V-shaped homodimer. Belongs to the SMC family. MukB subfamily.