GST Tag protein is one of important amino acid sequences that used for protein engineering for protein purification and protein detection purposes.
The GST Tag known as The Glutathione S-transferase (GST) is a Gene Fusion System that use for the expression, purification, and detection of fusion proteins produced in Eschericia coli and FDA approved organism for industrial bio process design. This fusion tagging system is based on inducible, high-level expression of genes or gene fragments as fusions with Schistosoma japonicum GST. Expression in E. coli yields fusion proteins with the GST moiety at the amino terminus and the protein of interest at the carboxyl terminus. This help less risks for protective active site of protein.
The engineered protein accumulates within the cell’s cytoplasm and can be separated by different molecular techniques in biotech lab. GST occurs naturally as a M r 26 000 protein that can be expressed in E. coli with full enzymatic activity, this will help evaluating indexes for reporting to FDA. Fusion proteins that possess the complete amino acid sequence of GST also demonstrate GST enzymatic activity and can undergo dimerization similar to that observed in nature and the cells. The crystal structure of recombinant S. japonicum GST from pGEX vectors has been determined and matches that of the native protein shows the characteristics of GST, as determined in pGEX-1N.
GST fusion proteins are purified from bacterial lysates by affinity chromatography techniques using immobilized glutathione. Engineered GST fusion proteins are captured by the affinity medium, and impurities are removed by washing. Fusion proteins are eluted under mild, non-denaturing conditions using reduced glutathione. The purification process preserves protein antigenicity and function that can help vaccine developers for primary research about purifying antigen proteins from pathogenic organisms. If desired, cleavage of the protein from GST can be achieved using a site-specific protease whose recognition sequence is located immediately upstream from the multiple cloning site on the pGEX plasmids. Fusion proteins can be detected using colorimetric or immunological methods in the laboratory. This is a simple method for detecting proteins and evaluate bio process for cloning and engineering the protein.
The GST Gene Fusion System has been used successfully in many applications including molecular immunology, the production of vaccines , and studies involving protein protein and merged DNA-protein interactions in Aptamer researches.