Click synthesis of ubiquitin dimer analogs to interrogate linkage-specific UBA domain binding

A new route to the synthesis of triazole-linked ubiquitin dimers (diUbs) as structural analogs of the seven diUbs is reported. Binding studies with the Lys48-specific UBA domain of the Mud1 protein suggest that they represent functionally suitable surrogates of their native counterparts linked by an isopeptide bond.