Protein Structure, Dynamics, and Folding via Ultrafast Multidimensional Infrared Spectroscopy

在这个由生命过程化学计划支持的奖项中，加州大学欧文分校的Nien-Hui Ge教授将使用飞秒多维红外（MultiD IR）光谱来研究肽的构象动力学、分布和折叠。目标是提供蛋白质结构和动力学的详细知识，这对理解生物过程至关重要。建议的工作包括研究螺旋结构和延伸结构之间的相互作用，确定非折叠肽的构象分布，研究超卷曲蛋白基序的关联，以及阐明蛋白质与膜的相互作用。多元红外实验将获得多肽的主链和侧链振动模式，并提供揭示结构单元之间的角度、距离和相关性的数据。选定位置的同位素编辑将用于提高空间分辨率，促进共振分配，并将该方法扩展到更大的肽和三级接触。研究温度、pH、溶剂和链长等因素对蛋白质稳定性的影响。多维红外光谱是一种相对较新的技术，它补充了核磁共振和x射线方法，能够在从飞秒到毫秒的大范围时间尺度内原位探测结构。将这种技术应用于肽的研究将使我们能够深入了解快速的构象波动和转变，这是传统技术难以做到的。这些实验数据对于验证理论预测和验证下一代力场是非常需要的。双色多维红外方法的进一步发展，类似于异核磁共振，将允许直接探测非常不同频率的振动器之间的耦合。将其应用于酰胺的振动模式将使构象测定具有更高的准确性。这些研究将提供肽结构和动力学的详细信息，并有助于理解蛋白质折叠。参与研究的研究生和博士后将获得先进的激光技术和核心物理科学的宝贵经验，可以加强他们未来的职业发展。将继续努力维护在线频谱数据库，并为K-12学生提供讲座和实验课程。

In this award supported by the Chemistry of Life Processes Program, Professor Nien-Hui Ge of the University of California at Irvine will use femtosecond multidimensional infrared (MultiD IR) spectroscopy to study the conformational dynamics, distributions, and folding of peptides. The goal is to provide detailed knowledge of protein structure and dynamics that is essential to the understanding of biological processes. The proposed work includes investigating the interplay between helical and extended structures, determining conformational distributions of nonfolding peptides, studying the association of supercoiled protein motifs, and elucidating protein-membrane interactions. MultiD IR experiments will access the backbone and side chain vibrational modes of peptides, and provide data that reveal the angles, distances, and correlations between structural units. Isotope editing at selected locations will be employed to enhance the spatial resolution, facilitate the assignment of resonances, and extend the method to larger peptides and tertiary contacts. The effects of temperature, pH, solvent, and chain length will be investigated to understand the factors that control protein stability. MultiD IR spectroscopy is a relatively new technique that complements NMR and X-ray methods, with the capability of probing the structure in situ as it evolves over a wide range of time scales, from femtosecond to millisecond. Applying this technique to the study of peptides will allow us to gain insights into rapid conformational fluctuations and transitions, not readily amenable to conventional techniques. Such experimental data are much needed for verification of theoretical predictions and validation of the next generation of force fields. Further development of two-color MultiD IR methods, analogous to heteronuclear NMR, will allow direct probing of coupling between vibrators of very different frequencies. Its application to the amide vibrational modes will enable conformational determination with higher accuracy. These studies will provide detailed information on peptide structure and dynamics, and contribute to the understanding of protein folding. Graduate students and postdoctoral researchers participating in the research will gain valuable experience with advanced laser techniques and core physical sciences that can strengthen their future career development. Efforts on maintaining an online spectrum database and contributing lectures and laboratory courses for K-12 students will be continued.