Greenfield Norma J
Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-5635, USA.
Nat Protoc. 2006;1(6):2891-9. doi: 10.1038/nprot.2006.244.
Circular dichroism (CD) is a useful spectroscopic technique for studying the secondary structure, folding and binding properties of proteins. This protocol covers how to use the intrinsic circular dichroic properties of proteins to follow their folding and unfolding as a function of time. Included are methods of obtaining data and for analyzing the folding and unfolding data to determine the rate constants and the order of the folding and unfolding reactions. The protocol focuses on the use of CD to follow folding when it is relatively slow, on the order of minutes to days. The methods for analyzing the data, however, can also be applied to data collected with a CD machine equipped with stopped-flow accessories in the range of milliseconds to seconds and folding analyzed by other spectroscopic methods including changes in absorption or fluorescence spectra as a function of time.
圆二色性（CD）是一种用于研究蛋白质二级结构、折叠和结合特性的有用光谱技术。本方案涵盖了如何利用蛋白质的固有圆二色性特性来跟踪其随时间的折叠和去折叠过程。其中包括获取数据以及分析折叠和去折叠数据以确定速率常数和折叠与去折叠反应级数的方法。该方案重点关注当折叠相对较慢，在几分钟到几天的时间尺度上时，利用圆二色性来跟踪折叠过程。然而，分析数据的方法也可应用于使用配备停流附件的圆二色性仪器在毫秒到秒的时间范围内收集的数据，以及通过其他光谱方法（包括吸收或荧光光谱随时间的变化）分析的折叠数据。
