Engineering the Performance of Artificial Inclusion Bodies Built of Catalytic β-Galactosidase

Abstract

One of the most critical bottlenecks in the application of industrial enzymes is the preservation of protein stability throughout the catalytic reaction, which often requires protein engineering and/or process optimization. In this context, we have designed and deeply characterized an efficient, stable, and reusable enzymatic platform based on the Escherichia coli β-galactosidase. The enzyme was assembled in vitro, by using divalent cations as molecular linkers, as stable protein microparticles showing catalytic activity. In this assembled microstructure, β-galactosidase exhibits a particular conformation within the microparticles, sharing structural traits (a high cross-parallel beta-sheet content) with the bacterial inclusion bodies and secretory amyloids from the mammalian endocrine system. This fact confers enhanced thermal stability compared to the soluble protein version and ensures high reusability in industry-oriented processes. On the other hand, among the catalog of cations tested as molecular linkers, a mixture of Ca2+ and Mg2+ offers the best performance to the catalytic particle. Altogether, these data offer clues for the application of a self-immobilized enzymatic platform with transversal applicability and enormous potential in biotechnology and biomedicine.