Dipolar recoupling NMR of biomolecular self-assemblies:: determining inter- and intrastrand distances in fibrilized Alzheimer's β-amyloid peptide
Dipolar recoupling NMR of biomolecular self-assemblies:: determining inter- and intrastrand distances in fibrilized Alzheimer's β-amyloid peptide
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DOI：
10.1016/s0926-2040(98)00086-1
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发表时间：
1998-12-01
影响因子：
3.2
通讯作者：
Botto, RE
中科院分区：
文献类型：
--
作者：
Gregory, DM;Benzinger, TLS;Botto, RE
我们展示了一种利用偶极重新耦合核磁共振技术研究自缔合生物聚合物结构的新方法。这种方法被应用于只含有单一同位素自旋标记(C-13)的纤维β-淀粉样蛋白(Aβ)多肽(阿尔茨海默病斑块的主要成分)的研究，方法是使用DRAW(偶极重新耦合与无窗序列)技术来测量C-13-C-13距离。单标记法简化了拉伸数据的分析，因为只存在线间接触，没有任何线内接触的可能性。如先前报道的[T.L.S.Benzinger，D.M.Gregory，T.S.Burkoth，H.Miller-Auer，D.G.Lynn，R.E.Botto，S.C.Meredith，(1998)13407.]，在所有研究的残基中观察到约5埃的接触；与每个氨基酸的扩展平行的β-折叠结构一致。在这里，我们提出我们的策略是完全可推广的，并提供了一种新的方法来表征任何迭代的、自缔合的生物聚合物。在概括和提炼我们的方法接近尾声时，我们在这篇文章中评估了我们之前的分析提出的几个问题。首先，我们考虑双量子(DQ)横向弛豫过程的影响。接下来，我们讨论各种多自旋几何对绘图数据建模的影响。还讨论了几个实际问题：(1)使用DQ过滤实验来证实绘制数据，或作为对适当放置同位素自旋标记的快速筛选评估；以及(2)通过冷冻干燥或冷冻制备的固体样品的比较。最后，将单标记法得到的数据与已知晶体结构的双C-13标记模型化合物的数据进行了比较。结果表明，这样的数据可以在复杂得多的多肽分子中获得。这些数据结合在一起，改进了DRAW方法，并证明了其在获得复杂生物分子聚集体(如Aβ)的高分辨率结构数据方面的精确度和实用性。(C)1998 Elsevier Science B.V.保留所有权利。
We demonstrate a new method for investigating the structure of self-associating biopolymers using dipolar recoupling NMR techniques. This approach was applied to the study of fibrillar beta-amyloid (A beta) peptides (the primary component of the plaques of Alzheimer's disease) containing only a single isotopic spin label (C-13), by employing the DRAWS (dipolar recoupling with a windowless sequence) technique to measure C-13-C-13 distances. The 'single-label' approach simplified analysis of DRAWS data, since only interstrand contacts are present, without the possibility of any intrastrand contacts. As previously reported [T.L.S. Benzinger, D.M. Gregory, T.S. Burkoth, H. Miller-Auer, D.G. Lynn, R.E. Botto, S.C. Meredith, (1998) 13407.], contacts of approximately 5 Angstrom were observed at all residues studied; consistent with an extended parallel beta-sheet structure with each amino acid in exact register. Here, we propose that our strategy is completely generalizable, and provides a new approach for characterizing any iterative, self-associating biopolymer. Towards the end of generalizing and refining our approach, in this paper we evaluate several issues raised by our previous analyses. First, we consider the effects of double-quantum (DQ) transverse relaxation processes. Next, we discuss the effects of various multiple-spin geometries on modeling of DRAWS data. Several practical issues are also discussed: these include (1) the use of DQ filtering experiments, either to corroborate DRAWS data, or as a rapid screening assessment of the proper placement of isotopic spin labels; and (2) the comparison of solid samples prepared by either lyophilization or freezing. Finally, data obtained from the use of single labels is compared with that obtained in doubly C-13-labeled model compounds of known crystal structure. It is shown that such data are obtainable in far more complex peptide molecules. These data,taken together, refine the DRAWS method, and demonstrate its precision and utility in obtaining high resolution structural data in complex biomolecular aggregates such as A beta. (C) 1998 Elsevier Science B.V. All rights reserved.