Protein–Ligand Interactions Using SPR Systems

Surface plasmon resonance (SPR) biosensor technology has become an important tool for drug discovery and basic research. SPR instruments are used for a wide variety of applications including determining the binding kinetics and affinity of an interaction, specificity studies, screening, assay development as well as concentration measurements. The interacting molecules may be proteins, peptides, lipids, viruses, nucleic acids, or small organic molecules such as fragments or drug candidates. The ease with which real time information can be obtained has changed many customer workflows in both antibody and small molecule/fragment interaction analysis, from label based and affinity/IC50 based workflows towards a label free and kinetic based workflow. This chapter focuses on applications for drug discovery, and outlines the experimental design for screening and selection of small molecules from a focused library. Also, determination of kinetics and/or affinity constants of selected ligands, using established SPR methodology is described, together with potential issues during assay development, running of the assay, and results interpretation.