Component of the DNA topoisomerase VI involved in chromatin organization and progression of endoreduplication cycles. Relaxes both positive and negative superturns and exhibits a strong decatenase activity. The B subunit binds ATP (By similarity). May be involved in cell proliferation and stress tolerance. ATP-dependent breakage, passage and rejoining of double-stranded DNA. Homodimer. Heterotetramer of two TOP6A and two TOP6B subunits (By similarity). Interacts with SPO11-2 and TOP6A3. Highly expressed in flowers before pollination. Expressed in roots and shoots. By auxin, abscisic acid (ABA) and benzylaminopurine. Belongs to the TOP6B family.