Spin Labeling Studies of Biomolecular Flexibility and Hydration

生命的过程涉及折叠和展开的生物大分子之间的大量相互作用。此外，特定的折叠形状和生物分子形状的变化可以调节细胞周期事件和重要的细胞功能。传统上，分子之间的所有相互作用都被认为像一把锁和一把钥匙一样紧密相连。然而，最近的研究表明，近30%的生物分子是未折叠的，未折叠的生物分子之间的相互作用可以是“特定的”和“瞬时的”。许多这种短暂的相互作用涉及到相分离(如油和水)，以形成亚细胞结构，负责聚集生命和复制所需的细胞功能所需的必要成分。这项工作旨在了解这些生物分子表面的水浓度和运动如何改变它们的形状、结构波动和相分离，从而揭示细胞控制和调节的重要方面。该项目还将为研究生、本科生和高中生提供独特的培训机会，包括与合作者交流经验以及参加会议和研讨会。不同的本科生将被招募以获得研究经验，使他们能够将本科工作融入研究环境中。来自贫困家庭的高中生将被招募到佛罗里达大学暑期科学教学计划中。新的RNA及其独特的多方面细胞功能的不断发现导致了将RNA生物学、化学和生物物理学结合在一起的丰富的研究领域。固有无序蛋白(IDPs)也越来越受到重视，因为它们通过形成无膜亚核细胞器来调节细胞功能。具体地说，这项工作利用定点定向自旋标记(SDSL)电子顺磁共振方法来表征甘氨酸核糖开关的构象采样、动力学和水化环境，甘氨酸核糖开关是一种大的动态RNA，调节基因表达和选择IDP蛋白质/肽。结果将揭示溶液环境条件如何调节构象灵活性和水化环境，并澄清构象平衡模型的细节，该模型描述了配体结合时适体间的相互作用，从而导致调节功能(在这种情况下是基因表达)。这项工作还将促进大RNA中自旋标记磁共振应用的发展，从而为可以在其他RNA系统中使用的工作奠定基础。对环境对国内流离失所者的影响的调查将提供分子层面的细节，说明环境参数(盐、浓度和其他分子)如何调节水合作用、结构和相分离。该项目的一个辅助方面是继续优化Overhauser动态核极化(ODNP)技术，以研究在核体等无膜细胞器中发现的分子浓度的大分子水化环境。

The process of life involves numerous interactions between folded and unfolded large biological molecules. Additionally, the specific folded shape and changes in the shapes of biological molecules can regulate cell cycle events and important cellular functions. Traditionally, all interactions between molecules were thought to fit together like a lock-and-key. However, recent research has shown that nearly 30% of biological molecules are unfolded and interactions between unfolded biological molecules can be "specific" and "transient". Many of these transient interactions involve phase separation (like oil and water) to form sub-cellular structures responsible for clustering the necessary ingredients necessary for cellular functions required for life and replication. This work aims to understand how water concentration and movement at the surface of these biological molecules can alter their shape, structural fluctuations, and phase separation; thus shedding light on important aspects of cellular control and regulation. The project will also provide unique training opportunities for graduate, undergraduate and high school students that include exchange experiences with collaborators and attendance at conferences and workshops. Diverse undergraduate students will be recruited for research experiences that will enable them to integrate their undergraduate course work into a research environment. High school students from underprivileged backgrounds will be recruited into the University of Florida Summer Science Teaching Program. The expanding discovery of novel RNAs and their unique multifaceted cellular capabilities has resulted in a rich arena of research interfacing RNA biology, chemistry, and biophysics. Intrinsically disordered proteins (IDPs) have also found a growing appreciation for their role in regulating cellular function through the formation of membraneless sub-nuclear organelles. Specifically, this work utilizes site-directed spin-labeling (SDSL) electron paramagnetic resonance approaches to characterize conformational sampling, dynamics and hydration environments of the glycine riboswitch; a large, dynamic RNA that modulates gene expression and select IDP proteins/peptides. The results will reveal how solution environmental conditions modulate conformational flexibility and hydration environment and clarify details of a model of conformational equilibrium that describes interaptamer interactions upon ligand binding that lead to regulatory function (in this case gene expression). This work will also add to the development of spin-labeling magnetic resonance applications in large RNAs; thus laying the foundation for work that can be utilized in other RNA systems. Investigations on the impact of environment on IDPs will provide molecular level details of how environmental parameters (salt, concentration and other molecules) can modulate hydration, structure and phase separation. An ancillary aspect of this project is to continue to optimize Overhauser dynamic nuclear polarization (ODNP) technologies for investigations of macromolecular hydration environment at molecular concentrations found within membraneless organelles such as the nuclear bodies.