Greenfield Norma J
Department of Neuroscience and Cell Biology, UMDNJ-Robert Johnson Medical School, Piscataway, NJ, USA.
Methods Mol Biol. 2004;261:55-78. doi: 10.1385/1-59259-762-9:055.
Circular dichroism (CD) spectroscopy is a useful technique for studying protein-protein interactions in solution. CD in the far ultraviolet region (178-260 nm) arises from the amides of the protein backbone and is sensitive to the conformation of the protein. Thus CD can determine whether there are changes in the conformation of proteins when they interact. CD bands in the near ultraviolet (350-260 nm) and visible regions arise from aromatic and prosthetic groups. There are also changes in these regions when proteins bind to each other. Because CD is a quantitative technique, changes in CD spectra are directly proportional to the amount of the protein-protein complexes formed, and these changes can be used to estimate binding constants. Changes in the stability of the protein complexes as a function of temperature or added denaturants, compared to the isolated proteins, can also be used to determine binding constants.
圆二色性（CD）光谱是研究溶液中蛋白质-蛋白质相互作用的一种有用技术。远紫外区域（178 - 260 nm）的CD源于蛋白质主链的酰胺基团，对蛋白质的构象敏感。因此，CD可以确定蛋白质相互作用时其构象是否发生变化。近紫外（350 - 260 nm）和可见光区域的CD谱带源于芳香族和辅基。蛋白质相互结合时，这些区域也会发生变化。由于CD是一种定量技术，CD光谱的变化与形成的蛋白质-蛋白质复合物的量成正比，这些变化可用于估计结合常数。与分离的蛋白质相比，蛋白质复合物的稳定性随温度或添加变性剂的变化也可用于确定结合常数。
