Entropic Springs in Tandem Repeat Proteins

该项目旨在了解控制一大类生物重要蛋白质功能的物理和化学原理，这些蛋白质被称为“串联重复蛋白”。特别是，研究重点是了解在肌肉纤维中发现的蛋白质中的串联重复蛋白结构与其转导力的能力之间的关系。这项研究涉及实验和计算技术的强大结合，由明尼苏达大学两个校区的科学家进行。它的成功将对生物系统中力转导的理解产生影响，并为解决生物科学中以前难以解决的问题建立新的方法。它将为本科生和研究生提供有价值的培训，他们将进行大部分的研究。更广泛地说，这项研究将加强两个校区的教育计划，并将与生物物理学会合作，丰富该领域已建立的区域教育计划。本研究的重点是含有串联重复序列的蛋白质，包括内在无序区域。肌营养不良蛋白作为本研究的模型蛋白。核心假设是，无序在这些蛋白质的能量学和力学中起着关键作用。因此，该项目结合了实验和计算工具，这些工具是探测蛋白质中无序到有序转变的最佳工具。第一个目标是将几种高分辨率量热技术与计算分子动力学模拟相结合，以验证该系统中的能量耗散涉及熵弹簧的假设。第二个目标采用电子顺磁共振（EPR）、荧光和核磁共振（NMR）技术，旨在量化蛋白质的动态紊乱。这一目的验证了增加串联重复次数增加蛋白质动力学和降低稳定性的假设。第三个目标是利用结合核磁共振和EPR原理的Overhauser动态核极化，探讨水动力学在这些过程中的作用。总体目标是促进对这些系统中能量学、结构动力学和力学之间耦合的理解。虽然这个项目的重点是肌营养不良蛋白，但这里建立的原理和技术将影响整个串联重复蛋白领域，这涉及许多神经肌肉功能。

This project aims to understand the physical and chemical principles that govern the function of a large class of biologically important proteins, called "tandem repeat proteins". In particular, the research focuses on understanding the relationship between tandem repeat protein structure in a protein found in muscle fibers and their ability to transduce force. The research involves a powerful combination of experimental and computational techniques, carried out by scientists at two University of Minnesota campuses. Its success will have impact on the understanding of force transduction in biological systems and establish a new approach to solving previously intractable problems in the biological sciences. It will provide valuable training for both undergraduate and graduate students, who will carry out most of the research. More broadly, this research will enhance educational programs at both campuses, and it will enrich an established regional educational program in this field, in collaboration with the Biophysical Society.This research focuses on proteins containing tandem repeats that include intrinsically disordered regions. Dystrophin serves as the model protein for this study. The central hypothesis is that disorder plays a critical role in the energetics and mechanics of these proteins. Therefore, the project combines experimental and computational tools that are optimal for probing disorder-to-order transitions in proteins. The first aim combines several high-resolution calorimetric techniques with computational molecular dynamics simulations to test the hypothesis that energy dissipation in this system involves entropic springs. The second aim employs electron paramagnetic resonance (EPR), fluorescence, and nuclear magnetic resonance (NMR) techniques that are designed to quantify dynamic disorder in proteins. This aim tests the hypothesis that increasing the number of tandem repeats increases protein dynamics and decreases stability. The third aim probes the role of water dynamics in these processes, using Overhauser dynamic nuclear polarization, which combines the principles of NMR and EPR. The overall goal is to advance understanding of the coupling between energetics, structural dynamics, and mechanics in these systems. While this project focuses on dystrophin, the principles and techniques established here will impact the entire field of tandem-repeat proteins, which are involved in numerous neuromuscular functions.