総説

フーリエ変換赤外差スペクトル法：蛋白質の活性部位構造と分子メカニズム解析

Fourier Transform Infrared Difference Spectroscopy: Analyses of Active-site Structures and Molecular Mechanisms of Proteins

野口　巧
Takumi NOGUCHI

酵素反応の分子機構を明らかにするためには，蛋白質の活性部位の詳細な構造情報を得ることが必要不可欠である．反応誘起フーリエ変換赤外（FTIR）差スペクトル法は，反応に伴う微小赤外吸収変化を検出することにより，蛋白質の活性部位における構造や反応を原子・分子レベルで調べることのできる手法である．特に，光を反応開始トリガとして用いる光誘起FTIR差スペクトル法は，様々な光応答性蛋白質の反応機構の研究に広く利用されてきた．本稿では，光誘起FTIR差スペクトルの測定・解析法について解説し，本手法の光応答性蛋白質の分子機構研究への応用例を紹介する．

For full understanding of the molecular mechanisms of enzymatic reactions, it is crucial to obtain the detailed structural information of the active sites of proteins. Reaction-induced Fourier transform infrared (FTIR) difference spectroscopy, which detects minute changes in the infrared absorption upon some reaction, is a powerful method to investigate the structures and reactions in the active sites of proteins at the atomic and molecular levels. In particular, light-induced FTIR difference spectroscopy that uses light as a trigger to initiate reactions has been extensively used in the studies of molecular mechanisms of photosensitive proteins. In this review article, the methods of measurement and analysis of light-induced FTIR difference spectra are described and applications to the studies of photosensitive proteins are introduced.

Keywords: Fourier-transform infrared spectroscopy, Photosensitive proteins, Molecular mechanism, Vibrational spectroscopy, Structural biology