Reisdorf W C, Krimm S
Biophysics Research Division, University of Michigan, Ann Arbor 48109, USA.
Biochemistry. 1996 Feb 6;35(5):1383-6. doi: 10.1021/bi951589v.
The Fourier transform infrared (FTIR) spectra of several coiled-coil proteins have been shown to possess unusual features in the amide I' region. Band maxima occur in the vicinity of 1630 cm-1, with component bands at higher frequency. This is well below the observed band at 1650 cm-1 found in standard alpha-helical polypeptides such as poly-L-alanine. Normal mode calculations on models of the coiled-coil structure have been performed to investigate this issue. We find that the observed band profile can be reproduced with very small random variation on the phi, psi of tropomyosin. We believe that the shift to lower frequency is due to additional hydrogen bonding of the solvent accessible backbone CO groups to water.
几种卷曲螺旋蛋白的傅里叶变换红外（FTIR）光谱在酰胺I'区域呈现出不同寻常的特征。谱带最大值出现在1630 cm-1附近，且有高频成分带。这远低于在标准α-螺旋多肽（如聚-L-丙氨酸）中观察到的1650 cm-1谱带。已对卷曲螺旋结构模型进行了简正模式计算以研究此问题。我们发现，通过对原肌球蛋白的φ、ψ角进行非常小的随机变化就能重现观察到的谱带轮廓。我们认为，向较低频率的偏移是由于溶剂可及的主链羰基与水形成了额外的氢键。
