Mutated Intramolecular Chaperones Generate High-Activity Isomers of Mature Enzymes

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• 作者：Mitsuru Nagayama ; Haruko Maeda ; Kouichi Kuroda ; Mitsuyoshi Ueda
• 刊名：Biochemistry
• 出版年：2012
• 出版时间：May 1, 2012
• 年：2012
• 卷：51
• 期：17
• 页码：3547-3553
• 全文大小：407K
• 年卷期：v.51,no.17(May 1, 2012)
• ISSN：1520-4995

文摘

The propeptide of carboxypeptidase Y precursor (proCPY) acts as an intramolecular chaperone that ensures the correct folding of the mature CPY (mCPY). Here, to further characterize the folding mechanism mediated by the propeptide, folding analysis was performed using a yeast molecular display system. CPYs 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 conformational microchanges through mutated intramolecular chaperones.