Multidimensional Femtosecond Correlation Spectroscopic Probes of Biomolecules

描述（由申请人提供）：淀粉样原纤维的形成和沉积与 20 多种神经退行性疾病相关。这些疾病包括阿尔茨海默病、帕金森病、亨廷顿病、传染性海绵状脑病和 II 型糖尿病。原纤维的寡聚体或其他原纤维前体被认为是主要的有毒物质，但淀粉样蛋白相关疾病中细胞和组织损伤的机制尚不清楚。提高我们对淀粉样蛋白生成多肽的结构、动力学及其毒性的了解对于开发淀粉样蛋白疾病的有效治疗方法至关重要。相干多维光学技术通过分子振动和电子运动对从红外到紫外范围内的精心定时和成形的飞秒激光脉冲序列的响应，为原纤维波动结构提供了新颖的探针。将开发旨在设计和解释这些多维光信号的模拟技术。通过优化脉冲偏振配置和形状获得的手性感应信号可提高分辨率并揭示精细细节。将在二维 (2D) UV 中预测芳香族侧链与蛋白质主链蛋白质/膜界面的侧链振动或电子激发之间的交叉峰模式。将制定解开多维光谱、提高分辨率和放大所需特征的策略。光学响应将用于表征小寡聚物及其在原纤维形成中的动力学。通过其大小和结构进行区分对于理解影响其形成的分子因素至关重要。已经表明，淀粉样蛋白生成多肽与细胞膜的相互作用可以加速原纤维形成并参与寡聚体或原原纤维的毒性。淀粉样肽聚集在脂质表面，渗入细胞膜并改变其渗透性，这可能会导致细胞损伤。该项目中开发的非线性光学探针可以直接监测膜上原纤维的形成如何损害双层的完整性。界面特异性偶数级光学技术将被设计用于研究膜上淀粉样蛋白生成多肽的聚集体并鉴定其毒性的光谱特征。 公共健康相关性：形成淀粉样原纤维并与多种人类疾病相关的错误折叠蛋白的结构、动力学和聚集机制将通过其对超短红外和紫外光脉冲序列的响应进行研究。将应用表面特定技术来探测膜上原纤维的毒性。将开发用于探测生物分子复合物的结合、波动和运动的模拟技术。

DESCRIPTION (provided by applicant): The formation and deposition of amyloid fibrils is associated with more than 20 neurodegenerative diseases. These include Alzheimer's, Parkinson's, Huntington's diseases, and the transmissible spongiform encephalopathies and type II diabetes. Oligomeric or other prefibrillar precursors of the fibrils are believed to be the main toxic species, but the mechanism of cell and tissue damage in amyloid-related diseases is not well understood. Improvement of our knowledge of the structure, kinetics of amyloidogenic polypeptides, and of their toxicity is essential for the development of effective treatments of amyloid disorders. Coherent multidimensional optical techniques provide novel probes into the fibril fluctuating structure through the response of molecular vibrational and electronic motions to sequences of carefully timed and shaped femtosecond laser pulses ranging from the infrared to the ultraviolet. Simulation techniques aimed at the design and interpretation of these multidimensional optical signals will be developed. Chirality-induced signals obtained by optimizing the pulse polarization configurations and shapes enhance the resolution and reveal fine details. Cross-peak patterns between side-chain vibrations or electronic excitations of aromatic side-chains with the protein backbone protein/membrane interfaces will be predicted in two-dimensional (2D) UV. Strategies for disentangling multidimensional spectra, enhancing the resolution, and amplifying desired features will be developed. The optical response will be used to characterize small oligomers and their kinetics in the formation of fibrils. Discrimination by their size and structure is of fundamental importance for understanding the molecular factors that affect their formation. It has been suggested that the interactions of amyloidogenic polypeptides with the cell membrane can accelerate fibril formation and are involved in the toxicity of oligomers or protofibrils. Amyloid peptides aggregate on the lipid surface penetrate into membranes and alter their permeability, which may contribute to cell damage. The nonlinear optical probes developed in this program can directly monitor how the formation of fibrils on a membrane damages the bilayer's integrity. Interface-specific even-order optical techniques will be designed to study aggregates of amyloidogenic polypeptides on membranes and identify spectroscopic signatures of their toxicity. PUBLIC HEALTH RELEVANCE: The structure, kinetics, and aggregation mechanism of misfolded proteins which form amyloid fibrils and are associated with several human diseases will be investigated through their response to sequences of ultrashort infrared and UV optical pulses. Surface specific technique will be applied for probing the toxicity of fibrils on membranes. Simulation techniques for probing the binding, fluctuations, and motions of biomolecular complexes will be developed.