Applications of Near-Infrared Raman Optical Activity to Biological Samples

许多生物辅因子，如光感受器中的光吸收发色团，本质上是平面分子。然而，蛋白质环境导致辅因子的结构扭曲，并且这种结构变化可以导致辅因子的化学性质的调节以使其生物活性最大化。我们最近将近红外罗阿应用于细菌视紫红质和光敏黄蛋白。这些研究表明，近红外激发使我们能够测量蛋白质环境中发色团的罗阿光谱。此外，利用DFT的罗阿光谱的计算提供了详细的结构信息，例如关于发色团的面外畸变的数据。这些发现将罗阿的适用性扩展到许多生物辅因子。

Many biological cofactors, such as light-absorbing chromophores in photoreceptors, are intrinsically planar molecules. A protein environment, however, causes structural distortions of the cofactor, and such structural changes can lead to a modulation of chemical properties of the cofactor to maximize its biological activity. We recently applied the near-infrared ROA to bacteriorhodopsin and photoactive yellow protein. These studies demonstrated that the near-infrared excitation allows us to measure the ROA spectra of a chromophore within a protein environment. Furthermore, calculations of the ROA spectra utilizing DFT provide detailed structural information, such as data about out-of-plane distortions of the chromophore. These findings extend the applicability of ROA to many biological cofactors.