Abstract

Every living organism relies on cell division for survival, which requires proper chromosomal organization and segregation. The SMC family of proteins is highly conserved in all branches of life and is known to play an important role in these processes. In Bacillus subtilis deletion of the Smc-ScpAB complex leads to severe defects in chromosome segregation. Presumably, Smc-ScpAB mediates the compaction and resolution of sister DNA molecules during cell division, however the molecular mechanism for this action is only poorly understood. A major aim of this work was to answer the question of how the ring-shaped Smc-ScpAB complex interacts with the chromosome. I thus developed a novel biochemical assay and found that the B. subtilis Smc-ScpAB complex entraps chromosomal DNA inside its ring in vivo. I then aimed in establishing the requirements for chromosomal entrapment. In a second study I contributed to, the impact of the Smc-ScpAB ATPase activity on its chromosome-wide interaction was studied using ChIP combined with whole-genome sequencing. In combination both studies allowed us to gain a deeper mechanistic insight on the interactions of B. subtilis Smc-ScpAB with the chromosome.