PURIFICATION AND ACTIVITY OF A WHEAT 9-KDA LIPID TRANSFER PROTEIN EXPRESSED IN ESCHERICHIA-COLI AS A FUSION WITH THE MALTOSE-BINDING PROTEIN

The cDNA encoding a wheat (Triticum durum) lipid transfer protein of 9 kDa was inserted into an Escherichia coli expression vector, pIH902, and expressed in the bacteria as a fusion with the maltose binding pro tein. The fusion protein was then purified to homogeneity and subjecte d to factor Xa cleavage, Although complete cleavage of the fusion prot ein was obtained, the expected lipid transfer protein was not recovere d; it appears to be degraded during protease digestion, However, a flu orescent lipid transfer assay demonstrated that the fusion protein has an activity identical to that of the wheat-purified lipid transfer pr otein. Thus, this expression system should allow further understanding of the structure/function relationships of wheat lipid transfer prote ins. (C) 1995 Academic Press, Inc.