Grossmann J G, Callaghan A J, Marcaida M J, Luisi B F, Alcock F H, Tokatlidis K, Moulin M, Haertlein M, Timmins P
Molecular Biophysics Group, STFC Daresbury Laboratory, Daresbury Science and Innovation Campus, Warrington, Cheshire WA4 AD, UK.
Eur Biophys J. 2008 Jun;37(5):603-11. doi: 10.1007/s00249-008-0278-z. Epub 2008 Feb 13.
Many macromolecules in the cell function by forming multi-component assemblies. We have applied the technique of small angle neutron scattering to study a nucleic acid-protein complex and a multi-protein complex. The results illustrate the versatility and applicability of the method to study macromolecular assemblies. The neutron scattering experiments, complementing X-ray solution scattering data, reveal that the conserved catalytic domain of RNase E, an essential ribonuclease in Escherichia coli (E. coli), undergoes a marked conformational change upon binding a 5'monophosphate-RNA substrate analogue. This provides the first evidence in support of an allosteric mechanism that brings about RNA substrate cleavage. Neutron contrast variation of the multi-protein TIM10 complex, a mitochondrial chaperone assembly comprising the subunits Tim9 and Tim10, has been used to determine a low-resolution shape reconstruction of the complex, highlighting the integral subunit organization. It shows characteristic features involving protrusions that could be assigned to the six subunits forming the complex.
细胞中的许多大分子通过形成多组分聚集体来发挥功能。我们应用小角中子散射技术研究了一种核酸 - 蛋白质复合物和一种多蛋白质复合物。结果说明了该方法在研究大分子聚集体方面的多功能性和适用性。中子散射实验对X射线溶液散射数据起到了补充作用，揭示了核糖核酸酶E（大肠杆菌中一种必需的核糖核酸酶）的保守催化结构域在结合5'单磷酸 - RNA底物类似物时会发生显著的构象变化。这为支持导致RNA底物切割的变构机制提供了首个证据。多蛋白质TIM10复合物是一种由Tim9和Tim10亚基组成的线粒体伴侣聚集体，通过中子对比变化已用于确定该复合物的低分辨率形状重建，突出了整体亚基组织。它显示出涉及突起的特征，这些突起可归因于形成该复合物的六个亚基。
