Chaperonin Complexes Monitored by Ion Mobility Mass Spectrometry
Chaperonin Complexes Monitored by Ion Mobility Mass Spectrometry
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DOI：
10.1021/ja8055134
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发表时间：
2009-02-04
影响因子：
15
通讯作者：
Heck, Albert J. R.
中科院分区：
文献类型：
--
作者：
van Duijn, Esther;Barendregt, Arjan;Heck, Albert J. R.
通过当代高分辨率结构生物学技术（如核磁共振、X射线晶体学和电子显微镜）对大分子功能蛋白组装体进行结构分析通常仍然具有挑战性。一个相当新的方法来产生结构信息，本地质谱，结合离子迁移质谱（IM-MS）的潜力，在这里强调。IM-MS允许评估蛋白质复合物离子的气相离子碰撞截面，其可以与蛋白质组装体的整体形状/体积相关，并且因此用于监测结构的变化。在这里，我们应用IM-MS研究几个（中间）伴侣蛋白复合物，可以在基板折叠。我们的研究结果表明，蛋白质组装保留其在气相中的溶液相结构特性，解决了质谱分析中的一个长期存在的问题。所有IM-MS数据的伴侣蛋白指向真正的基板内的GroEL腔被保留在气相中的埋葬。此外，发现GroEL、底物和辅伴侣蛋白之间的三元复合物的总体尺寸与空GroEL-GroES复合物的尺寸相似。我们还研究了减少电荷的效果，在电喷雾过程中获得的蛋白质复合物的伴侣蛋白的全球形状。在减少的电荷，蛋白质复合物被发现是更紧凑，可能占据更低数量的构象状态，能够改善离子迁移率分离。电荷状态的减少被发现不影响碰撞截面的伴侣蛋白组件中观察到的相对差异。
The structural analysis of macromolecular functional protein assemblies by contemporary high resolution structural biology techniques (such as nuclear magnetic resonance, X-ray crystallography, and electron microscopy) is often still challenging. The potential of a rather new method to generate structural information, native mass spectrometry, in combination with ion mobility mass spectrometry (IM-MS), is highlighted here. IM-MS allows the assessment of gas phase ion collision cross sections of protein complex ions, which can be related to overall shapes/volumes of protein assemblies, and thus be used to monitor changes in structure. Here we applied IM-MS to study several (intermediate) chaperonin complexes that can be present during substrate folding. Our results reveal that the protein assemblies retain their solution phase structural properties in the gas phase, addressing a long-standing issue in mass spectrometry. All IM-MS data on the chaperonins point toward the burial of genuine substrates inside the GroEL cavity being retained in the gas phase. Additionally, the overall dimensions of the ternary complexes between GroEL, a substrate, and cochaperonin were found to be similar to the dimensions of the empty GroEL-GroES complex. We also investigated the effect of reducing the charge, obtained in the electrospray process, of the protein complex on the global shape of the chaperonin. At decreased charge, the protein complex was found to be more compact, possibly occupying a lower number of conformational states, enabling an improved ion mobility separation. Charge state reduction was found not to affect the relative differences observed in collision cross sections for the chaperonin assemblies.