Analysis of protein folding memory with modification of intramolecular chaperons and its application

成功地在酵母细胞表面展示了带有突变前肽的CPY(羧基肽酶Y)，并通过选择性切割突变的前肽来纯化成熟的酶。对展示的CPY的活性和动力学的测定表明，前肽突变改变了mCPY的催化效率。虽然野生型和突变型CPY的成熟区具有相同的氨基酸序列，但突变型原CPY的mCPY催化效率高于野生型。这些结果表明，具有相同氨基酸序列的蛋白质可以通过分子内伴侣突变而折叠成具有微构象变化的异构体蛋白质。

CPYs (carboxypeptidase Y) with mutated propeptides were successfully displayed on yeast cell surface, and the mature enzymes were purified by the selective cleavage of mutated propeptides. Measurement of the activity and kinetics of the displayed CPYs indicated that the propeptide mutation altered the catalytic efficiency of mCPY. Although the mature region of the wild -type and mutant CPYs had identical amino acid sequences, the mCPYs from the mutant proCPYs had higher catalytic efficiency than the wild-type. These results indicate that proteins with identical amino acid sequence can fold into isomeric proteins with micro-conformational changes through mutated intramolecular chaperones.