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Administration of reseaches on principles of protein architecture

蛋白质结构原理研究的管理

基本信息

批准号：
09044076
负责人：
GO Nobuhiro
金额：
$ 1.47万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

Proteins, the molecule which play crucially important biological functions, possess its own pattern of conformational fluctuations depending on the three dimensional structure. The fluctuations are suppressed with decreasing temperature, and show a glass transition-like phenomenon at about 200 K.Below 200 K, the protein function is usually lost. Such observations indicate that the fluctuations acquired above the glass transition temperature is crucial for the biological functions. In principle, the glass transition phenomenon can be detected to the atomic detail by a cryo X-ray crystallographic study, as well as various spectroscopic techniques.This work was done by the cooperation between two groups, Go and Kidera in Kyoto University and Parak in Technical University Muenchen. Muenchen group did cryo X-ray measurements at various cryo-temperatures for myoglobin crystals. Kyoto group did analyses of diffraction data provided by Parak using an elaborated refinement method called the nor … More mal mode refinement. We have had close communication including each of two times visits from Kyoto to Muenchen and from Muenchen to Kyoto. Last December when Parak visited Japan, he presented a lecture on this topics in the 5-th workshop of "Principles of protein architectures".The results of the cooperative work is summarized as follows. The internal fluctuations,<R^<**>2>int, derived from the normal mode refinement of X-ray diffraction from myoglobin crystals was found to have temperature dependence of<R^<**>2>int = AT + Bwhere T is absolute temperature, and A an B are constants. The value of A has a good agreement with the value predicted by a normal mode analysis. This means that the conformational substates available below the glass transition temperature is the same as those above the transition temperature. This is why we do not observe abrupt increase in <R^<**>2>int at the glass transition temperature. Therefore, the value B represents the static disorder. This is the view of X-ray diffraction detecting the coherent scattering, which is totally different from the other spectroscopic techniques detecting the incoherent scattering, likeMossbauer absorption spectroscopy. Less

蛋白质是一种发挥着至关重要的生物功能的分子，根据其三维结构的不同，它具有自己的构象波动模式。随着温度的降低，蛋白质的起伏受到抑制，在200K左右呈现玻璃化转变现象，在200K以下，蛋白质的功能通常会丧失。这些观察表明，在玻璃化转变温度以上获得的波动对于生物功能是至关重要的。原则上，玻璃转变现象可以通过低温X射线结晶学研究以及各种光谱技术检测到原子的细节。这项工作是由京都大学的Go和Kidera以及慕尼黑工业大学的Parak两个小组合作完成的。慕尼黑团队在不同的低温下对肌红蛋白晶体进行了低温X射线测量。京都小组使用一种名为NOR…的精细方法对帕拉克提供的衍射数据进行了分析更多的模式精细化。我们进行了密切的沟通，包括从京都到慕尼黑和从慕尼黑到京都的两次访问。去年12月，帕拉克访问日本时，在第五届“蛋白质结构原理”研讨会上发表了关于这一主题的演讲。由肌红蛋白晶体X射线衍射的简正模修正得到的内涨落&lt；R^&lt；**&gt；2&gt；int具有温度依赖性&lt；R^&lt；**&gt；int=AT+B，其中T是绝对温度，A和B是常数。A值与简正波分析预测值有很好的一致性。这意味着低于玻璃化转变温度的构象亚态与高于转变温度的构象亚态是相同的。这就是为什么我们在玻璃化转变温度没有观察到&lt；R^&lt；**&gt；2&gt；int突然增加的原因。因此，值B代表静态无序。这是X射线衍射检测相干散射的观点，与穆斯堡尔吸收光谱等检测非相干散射的光谱技术完全不同。较少