Cultivation below 10 oC is an effective method to overcome the insolubility of recombinant proteins produced in Escherichia coli

Abstract

Biochemical, biophysical, and structural information on proteins provide opportunity for understand their biological functions. One of the limitations to the protein study is the difficulty in obtaining highly purified soluble protein. Protein expression in Escherichia coli (E.coli) at 15-25 oC is used to overcome this solubility limitation. However, many recombinant proteins are insolubly expressed even at those low temperatures. In this study, we show that recombinant proteins can be expressed as soluble forms at 6-10 oC without cold adapted chaperon systems. By using E. coli Rosetta-gami2(DE3), we obtained 1.8 and 0.9 mg of Cryptopygus antarticus mannanase (CaMan) and cellulase (CaCel) from 1 L culture grown at 6 and 10 oC, respectively. These proteins are also suitable for X-ray crystallography. Crystals of CaMan and CaCel diffracted to 2.4 Å and 2.6 Å resolution, respectively. Consequently, E. coli cultivation at 6– 10 oC is an effective method for overcoming a major hurdle of the inclusion body formation.ein expression in Escherichia coli (E.coli) at 15-25 oC is used to overcome this solubility limitation. However, many recombinant proteins are insolubly expressed even at those low temperatures. In this study, we show that recombinant proteins can be expressed as soluble forms at 6-10 oC without cold adapted chaperon systems. By using E. coli Rosetta-gami2(DE3), we obtained 1.8 and 0.9 mg of Cryptopygus antarticus mannanase (CaMan) and cellulase (CaCel) from 1 L culture grown at 6 and 10 oC, respectively. These proteins are also suitable for X-ray crystallography. Crystals of CaMan and CaCel diffracted to 2.4 Å and 2.6 Å resolution, respectively. Consequently, E. coli cultivation at 6– 10 oC is an effective method for overcoming a major hurdle of the inclusion body formation.