Artificial antifreeze proteins can improve NaCl tolerance when expressed in E. coli.

A chemically synthesized DNA fragment encoding an artificial antifreeze protein was expressed in E. coli as a translational fusion with a truncated protein A. Two constructions were made, with two and four antifreeze domains, respectively. The fusion proteins stimulated the growth of their bacterial host cells at inhibitory NaCl concentrations. The fusion protein carrying four antifreeze domains also conferred improved tolerance towards freezing.