RIG: Structural Biology of the Soil Bacterium M. xanthus Development and Motility

智力上的优点。土壤细菌黄色粘球菌是研究原核生物化学敏感信号转导的模式生物。这种细菌包含八个化学传感系统，调节发育基因的表达、运动和生物膜的形成。本项目的重点是阐明CHE3和FRZ化学传感系统中信号转导的调控机制，这两个系统分别对孢子发育和运动性起关键作用。Che3系统调节重要发育基因的转录，以响应外膜胁迫。这种调节是通过最近发现的调节蛋白CRDC(发育蛋白C的化学感觉调节蛋白)而产生的。这位研究人员的初步发现表明，CRDC通过与CheW3形成调控复合体来调节下游信号和孢子形成。溶液核磁共振方法将用于确定CheW3和CRDC的结构，并定义介导它们相互作用的残基。这些结构将为理解Che3化学感觉调控所需的生化和结构特征提供基础。FRZ化学感觉系统和MglA蛋白是运动性的关键调节因子。FRZ系统能够通过未知的机制激活MglA。反过来，激活的MglA又是通过与下游效应蛋白相互作用来调节运动性的关键。MglA蛋白与真核细胞中的GTP酶具有同源性，但其结合和水解鸟嘌呤核苷酸的能力尚未确定。这项研究将使用生化和生物物理方法来定义MglA的核苷酸结合特性以及与下游信号效应器相互作用的要求。这些基础研究的结果将为深入了解Che3和FRZ的化学感觉调控机制提供关键的结构和生物物理方面的见解，并为未来研究开发黄曲霉化学感觉调控的全面结构和机制图景提供框架。更广泛的影响。激发学生对科学和生化研究的兴趣对于培养以科学为基础的职业至关重要。首席调查员将通过两种方式让学生在本科生涯早期参与进来。首先，他将为现有的以生物物理实验为特色的实验生物化学课程设计和实施一个新的实验室部分。这一新颖的部分将补充现有的生物物理学教学课程，并使本科生接触到定量方法和生物物理技术。其次，他将启动一个新项目，为未被充分代表的少数族裔学生提供暑期研究机会。这项计划将由RIG赠款和生物化学部提供资金。总体而言，这些战略将有助于提供必要的学术和研究背景，以吸引和留住有才华的理科本科生。

Intellectual merit. The soil bacterium Myxococcus xanthus is a model organism for studying prokaryotic chemosensory signal transduction. This bacterium contains eight chemosensory systems that regulate developmental gene expression, motility, and biofilm formation. The focus of this project is to elucidate the regulatory mechanisms of signal transduction in the Che3 and Frz chemosensory systems, which are critical for spore development and motility, respectively. The Che3 system regulates transcription of important developmental genes in response to outer membrane stress. This regulation is derived through the recently identified regulatory protein, CrdC (chemosensory regulator of development protein C). This investigator's preliminary findings indicate that CrdC modulates downstream signaling and sporulation by forming a regulatory complex with CheW3. Solution NMR methods will be used to determine the structures of CheW3 and CrdC and define the residues that mediate their interaction. These structures will provide the foundation for understanding the biochemical and structural features required for Che3 chemosensory regulation. The Frz chemosensory system and the protein MglA are critical regulators of motility. The Frz system is capable of activating MglA by an unknown mechanism. Activated MglA, in turn, is critical for regulating motility through the interaction with downstream effector proteins. The MglA protein has homology to eukaryotic GTPases, but its ability to bind and hydrolyze guanine nucleotides has not been determined. This study will use biochemical and biophysical approaches to define the nucleotide-binding properties of MglA and the requirements for interacting with downstream signaling effectors. The results from these fundamental studies will provide key structural and biophysical insights into the mechanism of Che3 and Frz chemosensory regulation and the framework for future research towards developing a comprehensive structural and mechanistic picture of chemosensory regulation in M. xanthus. Broader impacts. Exciting students about science and biochemical research is critical for fostering science-based careers. The principal investigator will engage students early in their undergraduate career in two ways. First, he will design and implement a new laboratory section for the existing experimental Biochemistry course that features biophysical experiments. This novel section will complement the existing didactic courses in biophysics and expose undergraduate students to quantitative methods and biophysical techniques. Second, he will initiate a new program to provide summer research opportunities to under-represented minority students. This program will be funded by the RIG grant and the Department of Biochemistry. Collectively, these strategies will help provide the necessary academic and research background necessary to attract and retain talented undergraduate students in the sciences.