Efficient Expression and Refolding of Insolubilized Halophilic Starch-Binding Domain with Aggregation-Prone Peptide

Abstract

Soluble expression of halophilic starch-binding domain （SBD1） from Kocuria α-amylase was low due to its instability in recombinant host Escherichia coli cells. Here, the stable SBD1 protein was expressed efficiently with an aggregation-prone peptide tag in insoluble E. coli inclusion bodies （IBs）. Insoluble SBD1 protein with the tag, thus obtained, was easily solubilized with 8 M urea and refolded into an active form by simple urea dilution. The yield of active SBD1 with the tag after the solubilization / dilution method was 15 ～ 30 times higher than that of direct expression of SBD1 in soluble fraction.