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[摘要]：Circular dichroism (CD) spectroscopy is an important technique in structural biology for examining folding and conformational changes of proteins in solution. However, the use of CD spectroscopy in a membrane medium (and also in a nonhomogeneous medium) is limited by (i) high light scattering and (ii) differential scattering of incident left and right circularly polarized light, especially at shorter wavelengths (<200 nm). We report a novel methodology for estimating the distortion of CD spectra caused by light scattering for membrane-bound peptides and proteins. The method is applied to three proteins with very different secondary structures to illustrate the limits of its capabilities when calibrated with a simple soluble peptide ([Ac]ANLKALEAQKQKEQRQAAEELANAK[OH], standard peptide) with a balanced secondary structure. The method with this calibration standard was quite successful in estimating a-helix but more limited when it comes to proteins with very high beta-sheet or beta-turn content. |
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