Structures of archaeal DNA segregation machinery reveal bacterial and eukaryotic linkages

Plasmid partitioning superstructure system Partitioning and sharing DNA between dividing cells is critical for all domains of life. Prokaryotes must share certain plasmids as well as their genomic DNA to survive. Schumacher et al. studied the partition system that segregates a conjugative plasmid in the prokaryote Sulfolobus. The system consists of three proteins. AspA spreads along the plasmid DNA to create a protein-DNA superhelix. The ParA motor protein is linked to the protein-DNA superhelix through the ParB protein, which has structural similarities to eukaryotic centromere segregating proteins. Science , this issue p. 1120