Electron tomography reveals diverse conformations of integrin αIIbβ3 in the active state
Electron tomography reveals diverse conformations of integrin αIIbβ3 in the active state
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DOI：
10.1016/j.jsb.2005.03.005
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发表时间：
2005-06-01
影响因子：
3
通讯作者：
Yamada, T
中科院分区：
文献类型：
--
作者：
Iwasaki, K;Mitsuoka, K;Yamada, T
我们使用电子断层扫描确定了在活性状态下整合素α IIB β 3的三维（313）结构。我们发现，当我们为倾斜序列中的每个单个粒子重建3D体积时，我们获得了更好的密度图，而不是从整个标本区域的3D重建中提取含有粒子的子体积。100个粒子的三维层析重建显示，活化的α IIb β 3具有许多不同的构象。所有单个3D重建的平均值很好地适应了α V β 3头戴式耳机的晶体结构，确认了在密度图中分配给α和β亚基的位置。我们的研究中最引人注目的发现是β -亚基小腿的结构灵活性，而不是α -亚基腿的构象稳定性。β - I畴与杂化畴在活性态的原子结构吻合良好，杂化畴向外摆动，用于层析成像的粒子大多处于活性态。对三维重建集进行多元统计分析和分类表明，90%以上的重建被归为显示活动状态的类。我们的结果表明，电子断层扫描可以用于分类具有柔性结构的配合物，如整合素。(c) 2005爱思唯尔公司版权所有。
We used electron tomography to determine the three-dimensional (313) structure of integrin alpha IIB beta 3 in the active state. We found that we obtained better density maps when we reconstructed a 3D volume for each individual particle in the tilt series rather than to extract the particle-containing subvolumes from a 3D reconstruction of the entire specimen area. The 3D tomographic reconstructions of 100 particles revealed that activated alpha IIb beta 3 adopts many different conformations. An average of all the individual 3D reconstructions nicely accommodated the crystal structure of the alpha V beta 3 headpiece, confirming the locations assigned to the alpha-and beta-subunit in the density map. The most striking finding of our study is the structural flexibility of the lower leg of the beta-subunit as opposed to the conformational stability of the leg of the alpha-subunit. The good fit of the atomic structure of the beta I domain and the hybrid domain in the active state showed that the hybrid domain swings out, and most particles used for tomography are in the active state. Multivariate statistical analysis and classification applied to the set of 3D reconstructions revealed that more than 90% reconstructions are grouped into the classes that show the active state. Our results demonstrate that electron tomography can be used to classify complexes with a flexible structure such as integrins. (c) 2005 Elsevier Inc. All rights reserved.