ATPase subunit of a proteasome-like degradation complex; this subunit has chaperone activity. ATPase activity is much induced upon complex formation with ClpQ. A double ring-shaped homohexamer of ClpQ is capped on each side by a ring-shaped ClpY homohexamer. The assembly of the ClpQ/ClpY complex is dependent on binding of ATP (By similarity). Belongs to the ClpX chaperone family. HslU subfamily.