A time-efficient workflow to purify a library of alanine mutants of surface-exposed residues of the domain III of the envelope protein of dengue virus serotype 1

Dengue complex is formed by four viral serotypes that cause the disease of the same name. Dengue is the arthropod-borne disease with the highest incidence worldwide. The envelope glycoprotein comprises three structural domains. The domain III (DIII) induces neutralizing antibodies and is involved in the interactions with soluble plasma factors from human host. Recombinant DIII proteins have been used as analytical tools for the characterization of virus-host interactions and have been evaluated as sub-unit vaccines. Here, we report a purification procedure of recombinant DIII protein and seventy-five alanine mutants refolding by size exclusion chromatography that allows obtaining highly homogeneous protein preparations and suitable for efficient purification and folding check. Four positions are identified that significantly affect either the protein expression or folding of recombinant DIIIE1, K310, G304, D330 and P332.