Polyubiquitin recognition by AtSAP5, an A20-type zinc finger containing protein from Arabidopsis thaliana

► Stress associated proteins (SAPs) in plants contain A20-type zinc finger domains. ► AtSAP5 has the dialipathic patch instead the conserved diaromatic patch. ► AtSAP5 binds three linkage-specific polyubiquitin chains, but not monoubiquitin. ► A20_ZF of AtSAP5 is sufficient for polyubiquitin recognition. ► The dialipathic patch is critical in recognizing K48-linked polyubiquitin chains.