Multidimensional Femtosecond Correlation Spectroscopic Probes of Biomolecules

描述（由申请人提供）：淀粉样蛋白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氏病、帕金森氏病、亨廷顿氏病、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毒性物质，但淀粉样蛋白相关疾病中细胞和组织损伤的机制还不清楚。提高我们对淀粉样蛋白生成多肽的结构、动力学及其毒性的认识对于开发淀粉样蛋白疾病的有效治疗是必不可少的。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的范围内的仔细定时和成形的飞秒激光脉冲序列的响应，提供了进入纤维波动结构的新探针。将开发旨在设计和解释这些多维光信号的模拟技术。通过优化脉冲偏振结构和形状获得的手征诱导信号提高了分辨率，揭示了细节。在二维（2D）UV中预测芳香族侧链与蛋白质骨架蛋白质/膜界面的侧链振动或电子激发之间的交叉峰图案。将开发用于解开多维光谱、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的低聚物及其在原纤维形成中的动力学。通过它们的大小和结构进行区分对于理解影响它们形成的分子因素具有根本的重要性。已有研究表明，淀粉样蛋白多肽与细胞膜的相互作用可以加速原纤维的形成，并参与寡聚体或原纤维的毒性。淀粉样肽聚集在脂质表面，渗透到膜中并改变其渗透性，这可能导致细胞损伤。在这个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破坏双层的完整性。界面特异性偶阶光学技术将被设计用于研究膜上淀粉样蛋白多肽的聚集体，并确定其毒性的光谱特征。 公共卫生相关性：错误折叠的蛋白质，形成淀粉样纤维，并与几种人类疾病的结构，动力学和聚集机制将通过其响应序列的超短红外和紫外光脉冲进行研究。表面特异性技术将用于探测膜上纤维的毒性。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.