Multiscale structural dynamics of membrane protein complexes

膜蛋白复合体蛋白质的多尺度结构动力学是不断运动的，这些动力学对蛋白质的正确折叠和细胞功能至关重要。然而，实时蛋白质动力学如何影响折叠或调控构象变化尚不完全清楚。最近，我证明了细菌多药外排泵折叠过程中的动态变化会导致错误的蛋白质拓扑结构，并可能危及细菌产生耐药性的能力。外排泵除了导致耐药性和相关的健康问题外，还在细菌输出各种毒素、与其他细菌沟通以及帮助塑造周围生态系统方面发挥重要作用。我已经证明，蛋白质结构的动态变化很早就开始了，而蛋白质仍在核糖体上合成。当一种新的蛋白质被修饰、折叠、靶向并插入膜中时，这些动力学起着关键作用，但在完全成熟的蛋白质中动力学也是持续的。我最近使用实时方法来识别膜蛋白复合体的内在动力学，这些复合体能够实现功能构象的变化，并被细胞底物增强。然而，目前还不清楚这些动力学是如何在膜蛋白复合体中被控制或调节的。我的研究计划的长期目标是描述膜蛋白复合体内的动力学，这些复合体调节生物膜中的折叠和组装以及磷脂双层之间的通讯。了解外排泵组装和功能的实时动态将有助于深入了解细菌如何响应抗生素压力和产生耐药性，而且还将深化我们对膜蛋白复合体如何在脂质双层中折叠、组装和功能的一般知识。因此，我的综合研究计划将使用多药外排泵作为模型系统来研究膜蛋白复合体，在未来五年中，我将专注于两个具体目标：1)了解外排泵如何在正在进行的蛋白质合成过程中在生物膜中组装，以及2)表征驱动和调节抗生素外排的外排泵的结构动力学。通过了解膜-蛋白质复合体的实时动力学，我们有望有一天提前预测致病突变的影响，或推动针对这些复合体的下一代治疗药物的合理设计。

Multiscale structural dynamics of membrane protein complexes Proteins are constantly in motion, and these dynamics are critical for proper protein folding and cellular function. However, it is not entirely clear how real-time protein dynamics influence folding or regulate conformational changes. Recently, I have shown that dynamic changes during folding of a bacterial multidrug efflux pump can lead to erroneous protein topology and potentially compromise the capacity of bacteria to develop drug resistance. Efflux pumps, aside from contributing to drug resistance and associated health problems, also play fundamental roles in bacteria exporting various toxins, communicating with other bacteria, and helping to shape the surrounding ecosystem. I have shown that dynamic changes in protein structure start very early, while proteins are still being synthesized on the ribosome. These dynamics play critical roles as a new protein is modified, folded, targeted, and inserted into the membrane, but dynamics persist in fully mature proteins as well. I have recently used real-time methods to identify intrinsic dynamics of membrane protein complexes that enable functional conformational changes and are enhanced by cellular substrates. However, it is still unclear how these dynamics are controlled or regulated within membrane protein complexes. The long-term goal of my research program is to characterize dynamics within membrane protein complexes that regulate folding and assembly in biological membranes as well as communication across the phospholipid bilayer. Understanding the real-time dynamics of efflux pump assembly and function will provide insight into how bacteria respond to antibiotic stress and develop resistance, but also deepen our general knowledge of how membrane protein complexes fold, assemble, and function in a lipid bilayer. Accordingly, my comprehensive research program will study membrane protein complexes using multidrug efflux pumps as model systems, and, in the next five years, I will focus on two specific aims: 1) learn how efflux pumps are assembled in biological membranes during ongoing protein synthesis, and 2) characterize the structural dynamics of efflux pumps that drive and regulate antibiotic efflux. By understanding the real-time dynamics of membrane-protein complexes, we can hope to someday predict the effects of disease-causing mutations in advance, or fuel rational design of next-generation therapeutics targeting these complexes.