Infrared spectroscopy is a powerful technique for characterizing protein structure. It is now possible to record energy losses corresponding to the infrared region in the electron microscope and to avoid damage by positioning the probe in the region adjacent to the structure being studied. Spectra from bacteriorhodopsin, a protein that is predominately a ⍺ helix, and OmpF porin, a protein that is mainly β sheet show significant differences over a spectral range from ∼ 0.1 to 0.25 eV (∼ 1000 to 1800 cm-1 ). Although the energy resolution equivalent to 60 cm-1 is inferior to Fourier Transform InfraRed Spectroscopy (FTIR) the spectra are very sensitive to molecular orientation. Polar bonds aligned parallel to the specimen grid make particularly strong contributions to the energy loss spectra. Ultra-high resolution energy loss spectroscopy in the electron microscope can potentially add useful information to imaging and diffraction for determining the secondary structure misfolding believed to be responsible for dementia diseases such as Alzheimer's. This article is protected by copyright. All rights reserved.

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来自电子显微镜中记录的能量损失光谱的蛋白质二级结构特征

红外光谱是表征蛋白质结构的强大技术。现在可以在电子显微镜中记录对应于红外区域的能量损失，并通过将探针定位在与所研究结构相邻的区域来避免损坏。细菌视紫红质（一种主要是 ⍺ 螺旋的蛋白质）和 OmpF 孔蛋白（一种主要是 β 折叠的蛋白质）的光谱在 ∼ 0.1 到 0.25 eV (∼ 1000 到 1800 cm-1 ) 的光谱范围内显示出显着差异。尽管相当于 60 cm-1 的能量分辨率不如傅立叶变换红外光谱 (FTIR)，但光谱对分子取向非常敏感。与样品网格平行排列的极性键对能量损失谱的贡献特别大。电子显微镜中的超高分辨率能量损失光谱可以潜在地为成像和衍射增加有用的信息，以确定二级结构错误折叠被认为是导致痴呆症（如阿尔茨海默氏症）的原因。本文受版权保护。版权所有。