Protein expression system.

摘要

An expression system for producing and isolating large quantities of protein. This system employs an expression vector, comprising (a) a coding region for a glutathione-binding polypeptide (glutathione-s-transferase preferred), operatively connected to a promoter, (b) a second coding region in-frame with the first coding region, and (c) at least one restriction site between the first and second coding regions wherein a fusion protein of the first and second coding regions will result from expression of the vector. This vector is used in a host cell, which in turn is used in a process for isolating and purifying a protein. This process comprises (a) treating the host cell under conditions allowing expression of the vector, whereby a fusion protein of the first and second coding regions will be expressed; (b) exposing proteins from the host cell to glutathione resin, whereby the fusion protein will adhere to the resin; and (c) cleaving the expression product of the second coding region from the resin. Also described is a process for expressing a nucleic acid sequence, which comprises (a) inserting the nucleic acid sequence into a baculovirus expression vector in-frame with the first coding region; (b) placing the vector into a host cell; (c) treating the host cell under conditions allowing expression of the vector, resulting in expression of a fusion protein of the first coding region and the sequence inserted in step (a); (d) exposing proteins from the host cell to glutathione resin, whereby the fusion protein will adhere to the resin; and (e) treating the adhered fusion protein with a protease to release the expression product of the nucleic acid sequence from the resin. A baculovirus/Spodoptera frugiperda expression system is preferred. <IMAGE>