Oikawa Hiroyuki, Fujiyoshi Satoru, Dewa Takehisa, Nango Mamoru, Matsushita Michio
Department of Physics, Tokyo Institute of Technology, Meguro 152-8551, Japan.
J Am Chem Soc. 2008 Apr 9;130(14):4580-1. doi: 10.1021/ja078020p. Epub 2008 Mar 18.
The fluorescence excitation spectrum of a single chromophore molecule in a photosynthetic pigment-protein complex is known to change in time at liquid helium temperature. The spectral change reflects a conformational change of the protein to which the chromophore binds. This work follows the temporal behavior of the spectrum of a single chromophore in the temperature range between 5 adn 18 K. The temperature dependence reveals two types of conformational change of the protein, i.e., thermally activated motions over a potential barrier of ca. 0.1 kJ/mol and temperature-independent motions of tunneling of a proton.
已知在液氦温度下，光合色素 - 蛋白质复合物中单个发色团分子的荧光激发光谱会随时间变化。光谱变化反映了发色团所结合蛋白质的构象变化。这项工作追踪了单个发色团在5K至18K温度范围内光谱的时间行为。温度依赖性揭示了蛋白质的两种构象变化类型，即跨越约0.1kJ/mol势垒的热激活运动和质子隧穿的与温度无关的运动。
