Characterizing Methyl-Bearing Side Chain Contacts and Dynamics Mediating Amyloid β Protofibril Interactions Using 13Cmethyl-DEST and Lifetime Line Broadening
Characterizing Methyl-Bearing Side Chain Contacts and Dynamics Mediating Amyloid β Protofibril Interactions Using 13Cmethyl-DEST and Lifetime Line Broadening
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DOI：
10.1002/anie.201405180
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发表时间：
2014-09-22
影响因子：
16.6
通讯作者：
Clore, G. Marius
中科院分区：
文献类型：
--
作者：
Fawzi, Nicolas L.;Libich, David S.;Clore, G. Marius
与神经退行性疾病相关的蛋白质聚集体的形成和相互作用的许多细节对于传统的生物物理技术是不可见的。我们最近引入了N-15暗态交换饱和转移(DEST)和N-15寿命线展宽来研究淀粉样β蛋白(Aβ)单体与大的(2-80 MDA)原纤维Aβ聚集体交换的溶液骨架动力学和位置特定结合概率。在这里，我们使用C-13(甲基)DEST和寿命谱线展宽来探索Aβ-原纤维结合状态下含甲基侧链的相互作用和动力学。我们发现Aβ40的所有甲基都以非常快的有效横向驰豫速率填充到直接接触结合态，这表明侧链介导的直接结合到原纤维表面。这些数据与系留状态下C-13(甲基)-R-2(系留)值的位置特异性增强一致，为进一步了解原纤维结合状态的结构集成提供了进一步的见解。
Many details pertaining to the formation and interactions of protein aggregates associated with neurodegenerative diseases are invisible to conventional biophysical techniques. We recently introduced N-15 dark-state exchange saturation transfer (DEST) and N-15 lifetime line-broadening to study solution backbone dynamics and position-specific binding probabilities for amyloid beta (A beta) monomers in exchange with large (2-80 MDa) protofibrillar A beta aggregates. Here we use C-13(methyl) DEST and lifetime line-broadening to probe the interactions and dynamics of methyl-bearing side chains in the A beta-protofibril-bound state. We show that all methyl groups of A beta 40 populate direct-contact bound states with a very fast effective transverse relaxation rate, indicative of side-chain-mediated direct binding to the protofibril surface. The data are consistent with position-specific enhancements of C-13(methyl)-R-2(tethered) values in tethered states, providing further insights into the structural ensemble of the protofibril-bound state.