On the relationship between structure and catalytic effectiveness in solid surface-immobilized enzymes: Advances in methodology and the quest for a single-molecule perspective

Juan M.Bolivar^a,b,c, BerndNidetzky^a,b

Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Petersgasse 12, A-8010 Graz, Austria.

Abstract

The integration of enzymes with solid materials is important in many biotechnological applications, including the use of immobilized enzymes for biocatalytic synthesis. The development of functional enzyme-material composites is restrained by the lack of molecular-level insight into the behavior of enzymes in confined, surface-near environments. Here, we review recent advances in surface-sensitive spectroscopic techniques that push boundaries for the determination of enzyme structure and orientation at the solid-liquid interface. We discuss recent evidence from single-molecule studies showing that analyses sensitive to the temporal and spatial heterogeneities in immobilized enzymes can succeed in disentangling the effects of conformational stability and active-site accessibility on activity. Different immobilization methods involve distinct trade-off between these effects, thus emphasizing the need for a holistic (systems) view of immobilized enzymes for the rational development of practical biocatalysts.

Keywords: Enzyme, Immobilization, Biocatalyst, Solid-liquid interface, Single-molecule analysis.