Vibrational CD of polypeptides. XII. Reevaluation of the Fourier transform vibrational CD of poly(gamma-benzyl-L-glutamate).
Vibrational CD of polypeptides. XII. Reevaluation of the Fourier transform vibrational CD of poly(gamma-benzyl-L-glutamate).
复制标题
多肽的振动CD。
DOI：
10.1002/bip.360270503
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发表时间：
1988
期刊：
影响因子：
2.9
通讯作者：
Keiderling,TA
中科院分区：
文献类型：
--
作者：
Malon,P;Kobrinskaya,R;Keiderling,TA
使用新构建的基于傅里叶变换红外（FTIR）的振动CD（VCD）仪器，我们发现，消除检测器前的椭圆形收集镜，并将其替换为透镜，可以显著改善以前在FTIR-VCD中常见的吸收伪影问题。伪影水平的降低使聚（γ-苄基-L-谷氨酸酯）中酰胺1条带的FTIR-VCD条带形状与色散仪器的结果更一致。这些结果表明，用两种方法获得的光谱之间的差异主要不是分辨率的因素，而是更依赖于伪影水平。因此，先前报道的酰胺I VCD结果的去卷积及其随后在螺旋与激子机制方面的解释过分强调了光谱中的弱特征。基于吸收光谱的去卷积的结果仍然有效。进一步的新数据酰胺II和几个较低的能量转换，包括酰胺III区显示广泛的单符号的功能，但相反的意义，在这两个地区，这意味着他们的VCD通过相互耦合。
Using a newly constructed Fourier transform ir (FTIR) based vibrational CD (VCD) instrument, we have found that elimination of the ellipsoidal collection mirror before the detector and its replacement by a lens leads to a significant improvement in the absorption artifact problem often seen previously in FTIR‐VCD. Reduction in artifact level brings the FTIR‐VCD band shape of the amide 1 band in poly(γ‐benzyl‐L‐glutamate) into better agreement with that found with dispersive instruments. These results indicate that the difference between the spectra obtained with the two methods is not primarily a factor of resolution but is more dependent on artifact level. Thus the previously reported deconvolution of the amide I VCD results and their subsequent interpretation in terms of the helical vs. exciton mechanisms overemphasize weak features in the spectrum. Results based on deconvolution of the absorption spectrum remain valid. Further new data on the amide II and several lower energy transitions that encompass the amide III region show broad single‐signed features—but of the opposite sense—in the two regions, implying that their VCD arises through mutual coupling.