Real-Time Surface Plasmon Resonance (SPR) for the Analysis of Interactions Between SUMO Traps and Mono- or PolySUMO Moieties

International audience; Isolating endogenous SUMOylated proteins is a challenging task due to the high reversibility of this posttranslational modifi cation. We have shown that SUMO traps are useful tools for the enrichment and isolation of proteins modifi ed by SUMO in vitro and in vivo. To characterize the affi nity and specifi city of different SUMO chains for these traps, that are based on SUMO-interacting motifs, we have used realtime surface plasmon resonance (SPR), which allows a label-free analysis of protein/protein interactions. Here, a protocol to determine the affi nities of multivalent SUMO traps for polySUMO chains or mono-SUMO molecules by SPR is presented.