Thermolabile antifreeze protein produced in Escherichia coli for structural analysis

► A thermolabile antifreeze protein (AFP) was purified and crystallized. ► The yield of the natural 33-kDa AFP dimer from fish plasma was insufficient. ► Fully active recombinant AFP was made in E. coli Arctic Express®. ► Psychrophilic chaperonins helped produce AFP at 12 °C. ► Ice affinity purification was used to enrich AFP.