Figure 2.
The Ulp2 SIM peptide preferentially binds to longer linear SUMO chains. A, pulldown assay to detect binding between WT and mutant Ulp2 SIM peptide and linear SUMO chains. 1× loading is used for each sample. Alanine substitutions of residues in Ulp2's SIM are indicated in bold. B, pulldown assay to detect binding between WT and mutant Ulp2 CCR peptide and linear SUMO chains. Residues of Ulp2's CCR that were substituted by alanine are indicated in red. C–E, ITC analysis of 1×-, 4×-, and 6×-SUMO binding to the Ulp2 SIM peptide (DDDDEEIQIIENIDQSSKD). Dissociation constant (Kd) and binding stoichiometry (N) are indicated for each titration. F, ITC summary of the average of at least two independent measurements.