Analysis of AcrB and AcrB/DARPin ligand complexes by LILBID MS

► 3 different AcrB variants with DARPins were analyzed via LILBID-MS, SEC and AUC. ► AcrB/DARPin complex stoichiometry differs depending on the AcrB variant used. ► AcrB trimerization is due to strong monomer interaction via the periplasmic loop. ► DARPin binding is stronger than the interaction between the AcrB monomers. ► A 3.1 kDa mass attached to the AcrB monomer might represent detergent and/or lipids.