摘要
β-agarase AgaB appears to represent a new family of glycoside hydrolase; it is structurally and functionally different from other known agarases. In the present study, AgaB was expressed with a temperature-inducible expression system in E. coli BL21 (DE3) as a fusion protein bearing a C-terminal hexahistidine tag. The protein existed mainly in the form of inclusion body. After being washed and solubilized, AgaB in inclusion body was denatured and purified to electrophoretic purity by immobilized metal affinity chromatography. The purified AgaB was then refolded using a simple pulse dilution method, and the refolded AgaB showed a high specific hydrolysis activity of about 1600 units /mg protein. Forty milligrams of refolded pure protein were obtained from 1L of culture.
β-agarase AgaB appears to represent a new family of glycoside hydrolase; it is structurally and functionally different from other known agarases. In the present study, AgaB was expressed with a temperature-inducible expression system in E. coli BL21 (DE3) as a fusion protein bearing a C-terminal hexahistidine tag. The protein existed mainly in the form of inclusion body. After being washed and solubilized, AgaB in inclusion body was denatured and purified to electrophoretic purity by immobilized metal affinity chromatography. The purified AgaB was then refolded using a simple pulse dilution method, and the refolded AgaB showed a high specific hydrolysis activity of about 1600 units /mg protein. Forty milligrams of refolded pure protein were obtained from 1L of culture.
