Boosted activity by engineering the enzyme microenvironment in cascade reaction: A molecular understanding

Abstract

Engineering of enzyme microenvironment can surprisingly boost the apparent activity. However, the underlying regulation mechanism is not well-studied at a molecular level so far. Here, we present a modulation of two model enzymes of cytochrome c (Cty C) and d-amino acid oxidase (DAAO) with opposite pH-activity profiles using ionic polymers. The operational pH of poly (acrylic acid) modified Cyt C and polyallylamine modified DAAO was extended to 3–7 and 2–10 where the enzyme activity was larger than that at their optimum pH of 4.5 and 8.5 by 106% and 28%, respectively. The cascade reaction catalyzed by two modified enzymes reveals a 1.37-fold enhancement in catalytic efficiency compared with their native counterparts. The enzyme activity boosting is understood by performing the UV–vis/CD spectroscopy and molecular dynamics simulations in the atomistic level. The increased activity is ascribed to the favorable microenvironment in support of preserving enzyme native structures nearby cofactor under external perturbations.

Keywords

• Engineering of microenvironment
• Ionic polymers
• Multienzyme
• Boosted activity
• Molecular dynamics simulation
• Molecular understanding