Song Lingshuang, Yang Lin, Meng Jie, Yang Sichun
State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University , Beijing 100871, China.
Department of Nutrition, Case Western Reserve University , Cleveland, Ohio 44106, United States.
J Phys Chem Lett. 2017 Jan 19;8(2):347-351. doi: 10.1021/acs.jpclett.6b02673. Epub 2017 Jan 3.
We present a joint experimental-computational study to quantitatively describe the thermodynamics of hydrophobic leucine amino acids in aqueous solution. X-ray scattering data were acquired at a series of solute and salt concentrations to effectively measure interleucine interactions, indicating that a major scattering peak is observed consistently at q = 0.83 Å. Atomistic molecular dynamics simulations were then performed and compared with the scattering data, achieving high consistency at both small and wider scattering angles (q = 0-1.5 Å). This experimental-computational consistence enables a first glimpse of the leucine-leucine interacting landscape, where two leucine molecules are aligned mostly in a parallel fashion, as opposed to antiparallel, but also allows us to derive effective leucine-leucine interactions in solution. Collectively, this combined approach of employing experimental scattering and molecular simulation enables quantitative characterization of effective intermolecular interactions of hydrophobic amino acids, critical for protein function and dynamics such as protein folding.
我们开展了一项实验与计算相结合的研究，以定量描述疏水性亮氨酸氨基酸在水溶液中的热力学性质。在一系列溶质和盐浓度下获取了X射线散射数据，以有效测量亮氨酸间的相互作用，结果表明在q = 0.83 Å处始终观察到一个主要散射峰。随后进行了原子分子动力学模拟，并与散射数据进行比较，在小角度和宽角度散射（q = 0 - 1.5 Å）下均实现了高度一致性。这种实验与计算的一致性使我们首次得以窥见亮氨酸 - 亮氨酸相互作用的图景，其中两个亮氨酸分子大多以平行方式排列，而非反平行排列，同时也使我们能够推导出溶液中有效的亮氨酸 - 亮氨酸相互作用。总体而言，这种采用实验散射和分子模拟的组合方法能够对疏水性氨基酸的有效分子间相互作用进行定量表征，这对于蛋白质功能和诸如蛋白质折叠等动力学过程至关重要。
