EPR Studies of Protein-protein Interactions: Distances, Orientation and Molecular Modeling

肌球蛋白是一种机械力化学酶，能将三磷酸腺苷的化学能转化为机械力。与任何马达一样，无论是生物马达还是人造马达，力都是由特定部件的运动产生的。在过去的十年中，X射线结晶学和电子显微镜的成功揭示了处于ATPase循环不同中间状态的运动部件的解剖结构。现在需要做的是：(A)验证溶液中是否存在晶体结构；(B)找到涉及肌动蛋白和肌球蛋白的缺失中间状态；(C)及时关联结构，即从静态快照创建一部电影。这个项目使用电子顺磁共振光谱学来解决这些问题。它结合了光谱学、计算生物学、合成化学和分子生物学的最新发展。这些新的方法包括(A)新的距离测量技术，(B)位置定向自旋标记，(C)新设计的双功能自旋标记的使用，以及(D)从结构角度直接解释EPR信号。更广泛的影响：该项目预计将产生超越生物马达系统的影响。电子顺磁共振光谱学作为一种结构技术的发展有两个方面。随着这项技术变得越来越流行，这种发展是及时的，但针对结构生物学方面的理论落后于核磁共振波谱和电子显微镜的类似发展。该项目开发的工具和技术可用于解决许多结构生物学问题。更广泛的影响还包括教学和研究活动以及培训方面的一体化。该项目将继续培养化学、物理和生物方面的博士后研究员、研究生和本科生。

Myosin is a mechanochemical enzyme that transforms the chemical energy of ATP into mechanical force. As with any motor, biological or man-made, the force is generated by movement of specific parts. The success of x-ray crystallography and electron microscopy in the past decade revealed the anatomy of the motor parts in various intermediate states of the ATPase cycle. What needs to be done now is to: (a) verify that the crystal structures exist in solution; (b) find missing intermediate states that involve actin as well as myosin; (c) correlate the structures in time i.e. build a movie from static snapshots. This project addresses these questions using electron paramagnetic resonance spectroscopy. It combines recent developments in spectroscopy, computational biology, synthetic chemistry, and molecular biology. These novel approaches include (a) new distance measurement technique, (b) site directed spin labeling, (c) the use of newly designed bifunctional spin labels, and lastly, (d) direct interpretation of EPR signals in structural terms. Broader impacts: This project is expected to have an impact that transcends biological motor systems. Two aspects deal with the development of electron paramagnetic resonance spectroscopy as a structural technique. Such development is timely, as the technique is becoming more popular, yet the theory that targets structural biology aspects is lagging behind similar developments in nuclear magnetic resonance spectroscopy and electron microscopy. The tools and techniques developed in this project could be applied to solve many structural biology problems. The broader impacts also include integration of teaching and research activities as well as training aspects. This project will continue to train post-doctoral fellows, graduate students and undergraduate students at the interface of chemistry, physics, and biology.