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Development of instramentation of vibrational circular dichroism by Fourier transform spectroscopy and conformational studies of biopolymers

傅里叶变换光谱振动圆二色性仪器的发展和生物聚合物的构象研究

基本信息

批准号：
02558029
负责人：
SUGETA Hiromu
金额：
$ 3.33万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

Fourier transform infrared circular dichroism spectrophotometer was developed for investigating the secondary structures of biopolymers such as proteins and nucleic acids. The system was constructed using a Michelson interferometer (JASCO IRF-10 Interferometer), incorporatin, IRCD optical unit which consists of polarization modulation system and an MCF infrared detector, and the electronic unit which processes the interferogram associated with CD signal in addition to the ordinary absorption interferogram. Circular polarization modulation was achieved by a combination of a wire grid polarizer and a photoelastic modulator (PEM) made of ZnSe. The instrument is able to measure the wavenumber region from 2200 to 800 cm^<-1> with the sensitivity DELTA A=10^<-6> OD. VCD of N-acetyl N'-methylamides of several aminoacids (Ac-Ala-NHMe, Ac-Val-NHMe, Ac-Leu-NHMe, Ac-Phe-NHMe, and Ac-Pro-NHMe) were measured and analyzed in relation to the molecular conformations. It was found that the VCD of the NH stretching vibration (amide A band) depends on not only the local conformation of oligopeptides but also the intermolecular association by intermolucular hydrogen bond. VCD of tripeptides containing proline residue (Ac-Pro-Gly-NHMe and PivPro-GIY-NHMe) was studied as a model of beta -tum structure. The results were applied to the analysis of structural change in valinomycine on complexation with metal cation.

傅里叶变换红外圆二色光谱仪是一种用于研究蛋白质、核酸等生物大分子二级结构的仪器。该系统由迈克尔逊干涉仪（JASCO IRF-10 Interferometer）、偏振片、由偏振调制系统和MCF红外探测器组成的IRCD光学单元和除处理普通吸收干涉图外还处理与CD信号相关的干涉图的电子单元构成。圆偏振调制是通过线栅偏振器和ZnSe光弹调制器（PEM）的组合来实现的。该仪器能够测量2200至800 cm-1的波数区域<-1>，灵敏度为Δ A=10 μ <-6>OD。测定了几种氨基酸（Ac-Ala-NHMe、Ac-Val-NHMe、Ac-Leu-NHMe、Ac-Phe-NHMe和Ac-Pro-NHMe）的N-乙酰基N ′-甲基酰胺的VCD，并分析了它们与分子构象的关系。发现NH伸缩振动（酰胺A带）的VCD不仅取决于寡肽的局部构象，而且还取决于分子间氢键缔合。本文以含脯氨酸残基的三肽（Ac-Pro-Gly-NHMe和PivPro-GIY-NHMe）为β结构模型，研究了它们的VCD。将所得结果应用于缬氨霉素与金属离子络合后的结构变化分析。