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Low-frequency Raman Optical Activity of Nucleic Acids and Protein Crystals

核酸和蛋白质晶体的低频拉曼光学活性

基本信息

批准号：
12640395
负责人：
URABE Hisako
金额：
$ 2.18万
依托单位：
TOKYO KASEI GAKUIN UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640395/
关键词：
Raman optical activity collective vibration helical structure protein crystals α helix rich proteins 蛋白質結晶らせん骨格振動低振動数ラマンスペクトル DNA ノーマルモード

项目摘要

Raman optical activity (ROA) is observed as the difference Raman spectra between right and lefthanded circularly polarized incident lights. This effect is expected to be dominant for collectivevibrations of helical structure, which appear in the low-frequency region. We aimed to observelow-frequency ROA of biological molecules, such as nucleic acids, and proteins.The system is specially designed for low-frequency region measurements, consisting of amechanically rotating 1/4 λ, wave plate with linear polarizer, and a double monochrofnator with wave scan, and photon counting electronics.To avoid sample damage, the laser power is lowered, nevertheless , the long time exposure resulted degradation. We need transparent, and big sample not to disturb the polarization, which makes it difficult to prepare samples.We measured a helix rich protein solutions, such as poly-L-lysine in PHIO, insulin, apoferritin,and bacterio rhodopsin. We could find no trace ofnon-trivial signals. The ROA spectra of lysozyme crystals showed, hopefully, tiny signals. We will proceed to increase the S/N ratio.The neat liquids that maintain helical structure just above the melting points seem to be a future target for low-frequency ROA.

通过观察左旋和右旋圆偏振入射光的拉曼光谱差异，可以观察到拉曼光学活性(ROA)。对于出现在低频区的螺旋结构的集体振动，这一效应可望占主导地位。我们的目标是观察生物分子，如核酸和蛋白质的低频ROA。该系统是专门为低频区测量而设计的，它由机械旋转1/4λ、带线偏振片的波片、具有波扫描和光子计数电子的双单色器组成。为了避免样品损坏，降低了激光功率，但长时间曝光导致了退化。我们需要透明的、大的样品不干扰极化，这给样品的制备带来了困难。我们测量了富含螺旋的蛋白质溶液，如PHIO中的多L赖氨酸、胰岛素、载铁蛋白和细菌视紫质。我们找不到任何重要信号的踪迹。溶菌酶晶体的ROA光谱显示，希望是微小的信号。我们将继续提高S/N比。在熔点略高的地方保持螺旋结构的纯净液体似乎是未来低频ROA的目标。