MBP is part of a large class of proteins that aid in the uptake of small molecules. While it naturally resides in the periplasm, MBP can also be expressed at high yields in the cytoplasm. For different proteins, increased solubility, enhanced stability and markedly improved yields have been reported after fusion to MBP.
Maltose binding protein (MBP) tag is known to be used in genetic engineering to create a stable fusion product that does not appear to interfere with the bioactivity of the protein of interest or with the biodistribution of the MBP tagged product. The expression of polypeptides in-frame with maltose binding protein (MBP) allows for their easy purification from bacterial extracts under mild conditions, which employ a single affinity chromatographic step on amylose resin. This system and others based on the expression of fusion proteins utilize a specific protease cleaving site to facilitate correct cleavage of the fusion protein. Thus, the MBP system incorporates a factor Xa cleavage site at the carboxy terminus of the MBP sequence, and cleavage by factor Xa separates MBP from its partner protein. Many recombinant proteins have been engineered with MBP tags to facilitate the detection, isolation and purification of the proteins.
