Identification of β-turn and random coil amide III infrared bands for secondary structure estimation of proteins
Identification of β-turn and random coil amide III infrared bands for secondary structure estimation of proteins
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DOI：
10.1016/s0301-4622(99)00060-5
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发表时间：
1999-07-19
影响因子：
3.8
通讯作者：
Singh, BR
中科院分区：
文献类型：
--
作者：
Cai, SW;Singh, BR
傅里叶变换红外光谱越来越成为测定多肽和蛋白质二级结构的重要方法。在酰胺键的耦合和非耦合拉伸和弯曲模式产生的光谱区中，酰胺I和酰胺III的光谱带对二级结构折叠的变化最为敏感。Amide I光谱区（1700-1600 cm(-1)）虽然主要因其信号强而被广泛使用，但也存在一些限制，包括水振动带的强烈干扰，相对无结构的光谱轮廓，以及各种二级结构对应的旋转带重叠。相比之下，酰胺III光谱区（1350-1200 cm(-1)）虽然信号相对较弱，但没有上述限制。易于分辨和更好定义的酰胺ⅲ条带非常适合于蛋白质二级结构的定量分析。而酰胺III区已成功地用于测定α -螺旋和β -片（Fu, f - n）。，等人（1994）。光谱，48,1432-1441)，到目前为止，β匝和随机线圈对应的波段尚未确定。在本文中，我们首次描述了通过变性试剂选择性地增强随机线圈来识别β匝和随机线圈对应的酰胺III带，并利用带分配来估计几种蛋白质的二级结构。光谱波段分配如下：1330-1295 cm(-1)， α -螺旋；1295-1270厘米（-1），β匝数；1270-1250 cm（-1）随机线圈；1250-1220厘米（-1），β -薄片。上述赋值对二级结构元素的估计与x射线晶体学数据对二级结构的估计具有很好的相关性。(C) 1999 Elsevier Science B.V.版权所有
Fourier transform infrared spectroscopy is increasingly becoming an important method to determine secondary structure of peptides and proteins. Among the spectral regions arising out of coupled and uncoupled stretching and bending modes of amide bonds, amide I and amide III spectral bands have been found to be the most sensitive to the variations in secondary structure folding. Amide I spectral region (1700-1600 cm(-1)), although most commonly used primarily because of its strong signal, suffers from several limitations, including a strong interference from water vibrational band, relatively unstructured spectral contour, and overlap of revolved bands correspondingly to various secondary structures. In contrast, amide III spectral region (1350-1200 cm(-1)), albeit relatively weak in signals, does not have the above limitations. Easily resolved and better defined amide III bands are quite suitable for quantitative analysis of protein secondary structure. While amide III region has been successfully used for determination of alpha-helix and beta-sheets (Fu, F.-N., et al. (1994) Appl. Spectrosc. 48, 1432-1441), bands corresponding to beta-turns and random coils have not been identified, so far. In this paper, we describe, for the first time, identification of amide III bands corresponding to beta-turns and random coils by selectively enhancing random coils by treatment with a denaturing reagent, and secondary structure estimation of several proteins by using the band assignments. The assignments of spectral bands were as follows: 1330-1295 cm(-1), alpha-helix; 1295-1270 cm(-1), beta-turns; 1270-1250 cm(-1) random coils; and 1250-1220 cm(-1), beta-sheets. The estimations of secondary structural elements by the above assignments correlated quite well with secondary structure estimations from X-ray crystallography data. (C) 1999 Elsevier Science B.V. All rights reserved.