Sarver R W, Krueger W C
Department of Physical and Analytical Chemistry, Upjohn Co., Kalamazoo, Michigan 49001.
Anal Biochem. 1991 Apr;194(1):89-100. doi: 10.1016/0003-2697(91)90155-m.
An infrared (ir) method to determine the secondary structure of proteins in solution using the amide I region of the spectrum has been devised. The method is based on the circular dichroism (CD) matrix method for secondary structure analysis given by Compton and Johnson (L. A. Compton and W. C. Johnson, 1986, Anal. Biochem. 155, 155-167). The infrared data matrix was constructed from the normalized Fourier transform infrared spectra from 1700 to 1600 cm-1 of 17 commercially available proteins. The secondary structure matrix was constructed from the X-ray data of the seventeen proteins with secondary structure elements of helix, beta-sheet, beta-turn, and other (random). The CD and ir methods were compared by analyzing the proteins of the CD and ir databases as unknowns. Both methods produce similar results compared to structures obtained by X-ray crystallographic means with the CD slightly better for helix conformation, and the ir slightly better for beta-sheet. The relatively good ir analysis for concanavalin A and alpha-chymotrypsin indicate that the ir method is less affected by the presence of aromatic groups. The concentration of the protein and the cell path length need not be known for the ir analysis since the spectra can be normalized to the total ir intensity in the amide I region. The ir spectra for helix, beta-sheet, beta-turn, and other, as extracted from the data-base, agree with the literature band assignments. The ir data matrix and the inverse matrix necessary to analyze unknown proteins are presented.
已设计出一种利用光谱的酰胺I区域来测定溶液中蛋白质二级结构的红外（ir）方法。该方法基于康普顿和约翰逊（L. A. 康普顿和W. C. 约翰逊，1986年，《分析生物化学》155卷，第155 - 167页）给出的用于二级结构分析的圆二色性（CD）矩阵法。红外数据矩阵由17种市售蛋白质在1700至1600 cm⁻¹范围内的归一化傅里叶变换红外光谱构建而成。二级结构矩阵由这17种蛋白质的X射线数据构建，这些蛋白质具有螺旋、β折叠、β转角和其他（无规）二级结构元件。通过将CD和ir数据库中的蛋白质作为未知物进行分析，对CD和ir方法进行了比较。与通过X射线晶体学方法获得的结构相比，两种方法都产生了相似的结果，其中CD对螺旋构象的分析稍好，而ir对β折叠的分析稍好。伴刀豆球蛋白A和α - 胰凝乳蛋白酶的相对良好的ir分析表明，ir方法受芳香族基团存在的影响较小。由于光谱可以归一化为酰胺I区域的总红外强度，因此ir分析不需要知道蛋白质的浓度和样品池光程长度。从数据库中提取的螺旋、β折叠、β转角和其他结构的红外光谱与文献中的谱带归属一致。本文给出了分析未知蛋白质所需的ir数据矩阵和逆矩阵。
