Chemistry Department, University of California Irvine, USA.
Phys Chem Chem Phys. 2011 Feb 14;13(6):2394-400. doi: 10.1039/c0cp02047h. Epub 2010 Dec 6.
We report a first principles study of two dimensional electronic spectroscopy of aromatic side chain transitions in the 32-residue β-amyloid (Aβ(9-40)) fibrils in the near ultraviolet (250-300 nm). An efficient exciton Hamiltonian with electrostatic fluctuations (EHEF) algorithm is used to compute the electronic excitations in the presence of environmental fluctuations. The through-space inter- and intra-molecular interactions are calculated with high level quantum mechanics (QM) approaches, and interfaced with molecular mechanics (MM) simulations. Distinct two dimensional near ultraviolet (2DNUV) spectroscopic signatures are identified for different aromatic transitions, and the couplings between them. 2DNUV signals associated with the transition couplings are shown to be very sensitive to the change of residue-residue interactions induced by residue mutations. Our simulations suggest that 2DNUV spectra could provide a useful local probe for the structure and kinetics of fibrils.
我们报告了对 32 个残基β-淀粉样蛋白（Aβ（9-40））纤维中芳香族侧链跃迁的二维电子光谱的第一性原理研究，在近紫外（250-300nm）范围内。我们使用有效的包含静电涨落的激子哈密顿量（EHEF）算法来计算在环境涨落存在时的电子激发。通过空间的分子间和分子内相互作用是用高级量子力学（QM）方法计算的，并与分子力学（MM）模拟进行了对接。确定了不同芳香族跃迁的不同二维近紫外（2DNUV）光谱特征，以及它们之间的耦合。与跃迁耦合相关的 2DNUV 信号显示对残基突变引起的残基间相互作用的变化非常敏感。我们的模拟表明，2DNUV 光谱可以为纤维的结构和动力学提供有用的局部探针。
