Crystallographic studies on the ribosome, a large macromolecular assembly exhibiting severe nonisomorphism, extreme beam sensitivity and no internal symmetry.
Crystallographic studies on the ribosome, a large macromolecular assembly exhibiting severe nonisomorphism, extreme beam sensitivity and no internal symmetry.
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对核糖体的晶体学研究，核糖体是一种大分子组装体，表现出严重的非同构性、极高的光束敏感性和无内部对称性。
DOI：
10.1107/s010876739800991x
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Franceschi,F
中科院分区：
文献类型：
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作者：
Yonath,A;Harms,J;Hansen,HA;Bashan,A;Schlünzen,F;Levin,I;Koelln,I;Tocilj,A;Agmon,I;Peretz,M;Bartels,H;Bennett,WS;Krumbholz,S;Janell,D;Weinstein,S;Auerbach,T;Avila,H;Piolleti,M;Morlang,S;Franceschi,F
晶体，最好衍射到大约3 nm，已经从完整的大小核糖体亚基生长出来。 收集更高分辨率的X射线衍射数据所需的明亮的同步辐射，即使在低温下也会引起显着的衰减。然而，由于最近改进的小核糖体亚基晶体的合理同构性，在中等分辨率（5-6 μ m）下提取了可靠的相，并构建了可解释的五阶导数MIR图。 然而，对于大亚基的晶体，情况更加复杂，因为在较高的分辨率（2.7-7 μ m）下，它们遭受实质性的辐射敏感性、低水平的同构性、最长晶胞轴的不稳定性和各向异性镶嵌性。 为了深入了解这个不寻常的系统而构建的8μ MIR图可能为这些晶体的奇怪性质组合提供可行的推理以及未来改进的提示。平行的努力，其中电子显微镜重建的图像正在利用分子置换研究，也进行了讨论。
Crystals, diffracting best to around 3 Å, have been grown from intact large and small ribosomal subunits. The bright synchrotron radiation necessary for the collection of the higher-resolution X-ray diffraction data introduces significant decay even at cryo temperatures. Nevertheless, owing to the reasonable isomorphism of the recently improved crystals of the small ribosomal subunits, reliable phases have been extracted at medium resolution (5–6 Å) and an interpretable five-derivative MIR map has been constructed. For the crystals of the large subunits, however, the situation is more complicated because at higher resolution (2.7–7 Å) they suffer from substantial radiation sensitivity, a low level of isomorphism, instability of the longest unit-cell axis and nonisotropic mosaicity. The 8 Å MIR map, constructed to gain insight into this unusual system, may provide feasible reasoning for the odd combination of the properties of these crystals as well as hints for future improvement. Parallel efforts, in which electron-microscopy-reconstructed images are being exploited for molecular-replacement studies, are also discussed.