New Opportunities for Using Immobilized Ligands to Characterize Macromolecular Recognition and Design Recognition Molecules

Abstract

Abstract Characterization of protein interactions and interaction sites can provide a means both to learn about molecular recognition and assembly processes in biology and to identify and evaluate new recognition molecules of practical use in biotechnology. We have had a long-standing interest in using immobilized ligands as analytical tools for characterizing recognition mechanisms of proteins and other biological macromolecules. This interest started with analytical affinity chromatography (AAC). Recently, a newcomer among analytical technologies using immobilized ligands has appeared, namely the surface plasmon resonance (SPR) biosensor. The SPR biosensor, as AAC, enables detection and measurement of noncovalent interaction of a soluble macromolecule with a solid phase containing covalently attached ligand. Importantly, the biosensor offers several unique features including access to kinetics (hence deeper mechanistic understanding), ability to analyze molecules in mixtures (hence access to more biologically relevant conditions), and real-time observation of the interaction process (hence ability to observe interacting molecules as they form or are added). Recent results with HIV proteins including p24 self assembly and CD4-gpl20 interactions, as well as with interleukin 5 and its receptor reflect some of the growing uses of both AAC and the SPR biosensor as macromolecular recognition tools. Overall, the advent of the SPR biosensor and the likely follow-up development of other automated devices promise to stimulate evolution of the analytical use of immobilized ligands that started with AAC into a broad-based analytical solid phase science for the field of biomolecular recognition.