权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Crystallographics study of active ion transport

活性离子输运的晶体学研究

基本信息

批准号：
11308026
负责人：
TOYOSHIMA Chikashi
金额：
$ 19.91万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11308026/
关键词：
active transport Protein crystals membrane proteins ion pump electron crystallography X-ray crystallography ATPase

项目摘要

The first goal of this research was to determine the atomic structure of the Ca^<2+>-ATPase of sarcoplasmic reticulum, a representative member of P-type ion translocating ATPases, using very thin 3D crystals of X-ray quality that we generated in the presence of calcium. The next goal was to crystallise the enzyme in other different physiological conditions. This research proceeded much faster than we had expected. We have already obtained atomic models for 3 different physiological states (ElCa^<2+>, E2 and E2P) and have succeeded in crystallising the enzyme in two other states (E1ATP and E1P analogues). The atomic models revealed structural changes accompanying the dissociation of Ca^<2+> and phosphate. That is, 6 out of 10 transmembrane α-helices undergo a large scale rearrangements and 3 cytoplasmic domains, which are widely separated with bound Ca^<2+>, gather to form a compact single headpiece when calcium ions dissociate. Two of the transmembrane helices show movements that contain large components normal to the membrane plane. These helices move like pistons on the binding and release of Ca^<2+> and the cytoplasmic domains serve as a energy converter that drives the pistons. Thus, our results indicate that P-type ion translocating ATPases have a mechanism like mechanical pumps at an atomic scale.Some parts of these results were published in Nature in June 2000 and August 2002, and in PNAS in December 2002. These publications have collected considerable interests and been reviewed in detail in News and Views of Nature and Nature Structure Biology and in Editor's choice of Science. The results have been introduced already into world-standard text books of biochemistry and molecular biology.

本研究的第一个目标是利用我们在钙存在下产生的非常薄的X射线性质的3D晶体来确定P型离子转位ATPase的代表性成员肌浆网的Ca^&lt；2+-ATPase的原子结构。下一个目标是在其他不同的生理条件下使这种酶结晶。这项研究进展得比我们预期的要快得多。我们已经获得了3种不同生理状态(ELCA^&lt；2+&gt；，E2和E2P)的原子模型，并成功地在另外两种状态(E1ATP和E1P类似物)下结晶了酶。原子模型揭示了伴随着Ca~(2+)和P~(2+)解离的结构变化。也就是说，在10个跨膜α-螺旋中，有6个发生了大规模的重排，当钙离子解离时，广泛分离的3个细胞质结构域聚集在一起，形成一个紧凑的单一头盔。其中两个跨膜螺旋显示包含垂直于膜平面的大组件的运动。这些螺旋像活塞一样运动，结合和释放Ca^&lt；2+&gt；，胞质结构域充当驱动活塞的能量转换器。因此，我们的结果表明，P型离子转运ATPase具有类似于原子尺度上的机械泵的机制。这些结果的一部分发表在2000年6月和2002年8月的《自然》杂志上，以及2002年12月的《自然》杂志上。这些出版物引起了相当大的兴趣，并在《自然与自然结构生物学的新闻与观点》和《编辑的科学选择》中得到了详细的评论。这些成果已经被介绍到世界标准的生物化学和分子生物学教科书中。