Production of human β-actin and a mutant using a bacterial expression system with a cold shock vector

Abstract

Actin is the most abundant protein in the cytoplasm of most eukaryotic cells and is involved in a variety of cellular functions. It has been difficult to produce actin in bacterial expression systems in good yields. In this study, we developed a new simple method for the production of recombinant actin in Escherichia coli cells. Human β-actin was successfully expressed using a cold shock vector, pCold, in the bacterial expression system. The expressed β-actin (hexahistidine-tagged) was separated with a Ni-chelating resin, followed by a polymerization/depolymerization cycle or column chromatography with the Ni-chelating resin. The purified recombinant β-actin showed a normal polymerization ability compared with β-actin purified from human platelets. We produced a recombinant mutant actin with a Gly-168Arg mutation in the system and confirmed that it exhibited an impaired polymerization ability. The system developed in this study will provide a useful method for the production of actin isoforms and their mutants.