Intermediate step of cohesin’s ATPase cycle allows cohesin to entrap DNA

Significance Cohesin is an ATPase that organizes chromosome structure for chromosome segregation, gene expression, and DNA repair. Its function has been implicated in the prevention of cancer, birth defects, and several human disorders. Cohesin uses its ATPase, through elusive mechanisms, to tether DNA molecules and possibly translocate along them. Our analysis of cohesin with an active site mutation and an ATP analog suggest that a function of the ATPase is to generate an intermediate nucleotide state of cohesin ATPase, likely cohesin ADP-Pi , that is competent to stably tether two DNA molecules. This state is potentially a trapped intermediate derived from a DNA translocation activity. These results suggest how the regulation of cohesin ATPase may interconvert its tethering and putative motor activity.