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

肌凝蛋白是一种机械化学酶，能将ATP的化学能转化为机械力。与任何电机一样，无论是生物的还是人造的，这种力都是由特定部件的运动产生的。在过去的十年里，x射线晶体学和电子显微镜的成功揭示了atp酶循环的各种中间状态的运动部件的解剖结构。现在需要做的是：(a)验证溶液中存在晶体结构；(b)发现缺失的涉及肌动蛋白和肌凝蛋白的中间状态；(c)及时关联结构，即从静态快照构建电影。本项目利用电子顺磁共振波谱技术解决了这些问题。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。这些新方法包括(a)新的距离测量技术，(b)定向自旋标记，(c)使用新设计的双功能自旋标记，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运动系统的影响。两个方面论述了电子顺磁共振波谱作为一种结构技术的发展。随着技术的日益普及，这种发展是及时的，然而，针对结构生物学方面的理论落后于核磁共振波谱学和电子显微镜的类似发展。本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的整合以及培训方面。本项目将继续培养化学、物理、生物交叉领域的博士后、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.