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Solution X-ray scattering study on protein structure at high pressure using synchrotron

使用同步加速器对高压蛋白质结构进行溶液 X 射线散射研究

基本信息

批准号：
07808076
负责人：
KATO Minoru
金额：
$ 1.41万
依托单位：
Ritsumeikan University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07808076/
关键词：
solutin X-ray scattering SOXS protein structure pressure synchrotron radiation radius of gyration lysozyme myoglobin X線溶液錯乱蛋白質圧力効果

项目摘要

The purposes of this study are to develop the high-pressure solution X-ray scattering instrument and to apply the technique to the protein solution system. In the development work, we have composed the high-perfomance high-pressure instrument (max.500 MPa) by improving the design of the backup ring and the mechanics of pressure generation. In the application work, we have measured the solution X-ray scattering (SOXS) from lysozyme and myoglobin under pressure. For the estimation of compressibility of protein, we determined the radius of gyration (Rg) of lysozyme under pressure, up to which the protein keeps the native structure. The Rg of lysozyme decreases with increasing pressure : 14.85 * at 1 atm, 14.46 * at 300 MPa. It means that the change in Rg is -0.13 */100 MPa. This value in the absolute is remarkably larger than -0.04 */100 MPa. To clarify the characteristic of pressure unfolding of protein, we measured SOXS from myoglobin at PH 4.4 under pressure up to 30 MPa. The pressure dependence of Rg showed the sigmoid curve reaching to the maximum at 300 MPa. It indicated that the midpoint pressure is about 200MPa, and that the protein prefectly denatured at 300 MPa. The values of Rg at 1atm and 300 MPa are 17.5 * and 21.5 *, respectively. The value at 300 MPa is remarkably smaller than the values pound 30 * reported for the denaturant unfolding of myoglobin. The value for pressure unfolding is rather close to that for molten globule state.

本研究的目的是研制高压溶液X射线散射仪，并将该技术应用于蛋白质溶液体系。在研制工作中，通过对支撑环的设计和压力产生机理的改进，研制出了高性能的高压仪表(最高可达500兆帕)。在应用工作中，我们测量了压力下溶菌酶和肌红蛋白的溶液X射线散射(SOXS)。为了估计蛋白质的可压缩性，我们测定了溶菌酶在压力下的旋转半径(Rg)，直到达到这个半径，蛋白质才能保持天然结构。溶菌酶的Rg随压力的增加而减小，在1大气压下为14.85*，在300 Mpa时为14.46*。这意味着Rg的变化为-0.13*/100 Mpa。绝对值明显大于-0.04*/100兆帕。为了阐明蛋白质压力去折叠的特征，我们测量了PH值为4.4、压力高达30兆帕的肌红蛋白中的SOXS。Rg的压力依赖关系显示S型曲线在300 Mpa时达到最大。结果表明，中点压力在200 mpa左右，在300 mpa时变性效果最好。在1atm和300 Mpa下的Rg分别为17.5*和21.5*。在300兆帕下的数值明显小于报道的肌红蛋白变性去折叠的数值。压力展开值与熔融球状态的压力值非常接近。