Selective IR measurement of chromophore of fluorescent proteins in aqueous solution

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K14592
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 32010:Fundamental physical chemistry-related
• Research Institution: Okayama University of Science
• Principal Investigator: Takahashi Hirona 岡山理科大学, 理学部, 講師 (00803529)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 共鳴IR法 / 蛍光タンパク質 / 発色団 / 赤外分光計測 / 振動緩和過程

Outline of Final Research Achievements

Recently, we have developed the resonance IR spectroscopy for fluorescent molecules in water by combining IR super-resolution technique and transient fluorescence detection IR (TFD-IR) method. In this study, we applied this method to fluorescent protein and succeeded in the selective IR measurement of chromophores. The S/N ratio of IR spectra was quite high although the concentration of fluorescent proteins was small. Because no peak appeared in the amide I region, it is concluded that the selective IR measurement of fluorescent protein chromophore was succeeded in. It was also found the different spectral features of fluorescent proteins, which had similar chromophore. This might come from the difference of the molecular structure of chromophores. In addition, we measured the time profile of the intensity of resonance IR signals and observe the vibrational relaxation process.

Free Research Field

物理化学

Academic Significance and Societal Importance of the Research Achievements

本研究ではTFD-IR分光法と顕微鏡技術を利用した共鳴IR法により、蛍光タンパク質発色団部位の選択的な赤外分光計測法を確立し、発色団の分子構造、電子状態および周囲との相互作用が吸収・発光特性にどのように影響するのか議論を行った。希薄な水溶液中においても高いS/N比で蛍光タンパク質発色団部位の赤外分光計測に成功しているが、これは共鳴IR法でのみ実現できる新規かつ唯一のものであり、従来の振動分光法では達成しえなかった成果である。