Physico-Chemical Characterization of Permutated Variants of Chaperone GroEL Apical Domain

Abstract

At biosynthetic production of hydrophobic recombinant proteins there is often a problem of their aggregation in so-called inclusion bodies, after which these proteins are difficult to renature. Obtaining such proteins in soluble forms is a formidable obstacle on the way of using them. One of possible solutions for this problem is the creation of fusion constructs with a leading protein. Previously, we have developed a system for biosynthetic production of insoluble hydrophobic proteins as a part of a fusion construct with a leader based on chaperone GroEL apical domain (GrAD, GroEL Apical Domain). Expressed as a part of a fusion with GrAD, two initially insoluble proteins were successfully obtained in soluble form. Still, such a system may have limitations in use, because supporting hydrophobic proteins in soluble state requires their interaction with GrAD substrate binding surface, which implies correct mutual orientation of proteins constituent parts of the construct, and for some target proteins such interaction may be sterically impeded. To enlarge the capability of using GrAD, the strategy of making permutations was used, which consists in linking original GrAD N- and C-termini with a linker and creating new N- and C-termini situated in closer proximity to the GrAD substrate binding surface. This work describes production and the study of physico-chemical properties of two permutated GrAD variants intended to be used as leaders in fusion constructs.