Abstract
There are a lot of genes encoding membrane proteins in plants. However, it is difficult to analyze their biological functions, because membrane proteins are active only as integrated form in membranes and are insoluble after separation from membranes. Hence, functions of almost all of those proteins remain to be clarified. In this research, we tried to improve proteoliposome reconstituting system for analyzing plant membrane proteins by using wheat germ cell-free protein synthesis system. At first, we started this study by testing phosphoenolpyruvate/phosphate translocator OsPPT1 as a model protein. OsPPT1 was easily synthesized by the cell-free system, but the synthesized proteins were insoluble. In order to improve the solubility of the call-free synthesized OsPPT1, we tested several detergents, and found that some detergents increased the solubility of the products in the cell-free reaction. We eventually succeeded in detection of the phosphate-transporting activity of OsPPT1 on liposome prepared from phosphatidylcholine.
