Rationally tailoring the halophilicity of an amylolytic enzyme for application in dehydrating conditions

Abstract

Rationally engineering mesophilic enzymes to function efficiently in dehydrating conditions is of great interest since saline and hypersaline environments are prevailing in many industrial processes. Here, targeted mutagenesis and structural comparison identified that the surface charge distribution is a structure feature in determining the halophilicity of α-amylase Ha-Amy, which enables to rationally tailor protein halophilicity by engineering local charge density on protein surface. Importantly, such modification can be applied to non-catalytic domains, which is highly appreciated in protein engineering in consideration of minimizing the adverse effects on catalytic efficiency. Our results not only provide more insights into the protein salt-adaptation mechanisms but allow to confer salt-tolerant property on mesophilic proteins for actual application in dehydrating conditions.