Crystal structure of the N-terminal region of human Topoisomerase IIβ binding protein 1

► The crystal structure of the N-terminal region of human Topoisomerase IIβ binding protein 1 is determined at 2.4 Å resolution. ► Uncover previously unrecognized three tandem BRCT domains. ► A unique surface pocket of BRCT0 domain is defined. ► Tandem BRCT1-2 domains are the binding region for pSer387 of Rad9.