Structural Basis of Antimicrobial Peptide Sensing and Resistance

项目总结/摘要 抗药性细菌的增加是对人类健康的一个迅速演变的威胁。病原菌有 开发了几种机制来对抗抗菌化合物带来的威胁，并在利基市场中生存下来。 人体内的环境。我们实验室的首要目标是了解一个分子 水平病原菌如何利用特定的膜蛋白复合物，以满足这些专门的需求。我们 特别强调理解膜转运蛋白的结构和功能， 分子和信号穿过细菌膜，蛋白质复合物，使细菌能够感知和 对环境刺激作出反应。为了实现这些目标，我们通常将联合收割机高分辨率冷冻- 电子显微镜与生物化学和计算方法，以获得深入了解结构， 构象动力学和膜转运蛋白和信号复合物的整体功能。 我们在颁奖期间的主要重点将是了解革兰氏阳性菌如何使用 专门的膜蛋白机械来感知和逃避抗微生物肽的攻击。抗菌 肽如万古霉素是目前临床使用的一些最有效的抗生素 被认为是最后的治疗选择。然而，感染革兰氏阳性微生物，如 耐万古霉素肠球菌或葡萄球菌继续威胁医疗机构， 受感染的患者，治疗选择有限。许多革兰氏阳性菌表达膜蛋白 被称为“Bce模块”（BCEMs）的复合物，其包含ABC转运蛋白和双组分系统 它们协同工作，感知并响应抗微生物肽的攻击。我们的主要目标是获得 全面了解BCEM的ABC转运蛋白组分如何识别和提供耐药性 以及ABC转运蛋白的构象循环如何通过抗微生物肽启动信号传导。 双组分系统通过通量传感机制。结构、构象和构象的全面研究 动力学、动力学机制和BCEM的体内活性将被执行，以了解BCEM如何 这些模块的组分协同工作以感测和响应抗微生物肽。 在我们研究的高潮，我们将建立一个结构驱动的理解， 膜蛋白复合物，允许革兰氏阳性病原体感测和响应不同的抗微生物 缩氨酸我们的长期愿景是建立一个全面的模型，不同的蛋白质机器所使用的 微生物病原体来规避我们最强大的抗生素。详细的结构和功能分析 这些蛋白质复合物将为开发新的和改进的抗微生物化合物奠定基础， 耐药微生物感染的靶向治疗。

Project Summary/Abstract The rise of drug resistant bacteria is a rapidly evolving threat to human health. Pathogenic bacteria have developed several mechanisms to battle the threat posed by antimicrobial compounds and survive in niche environments within the human body. The overarching goal in our laboratory is to understand at a molecular level how pathogenic bacteria utilize specific membrane protein complexes to meet these specialized needs. We place a particular emphasis on understanding the structure and function of membrane transporters that move molecules and signals across bacterial membranes, and protein complexes that allow bacteria to sense and respond to environmental stimuli. In order to achieve these goals, we routinely combine high-resolution cryo- electron microscopy with biochemical and computational methods to gain insight into the structure, conformational dynamics, and overall function of membrane transporters and signaling complexes. Our primary focus during the award period will be to understand how Gram-positive species use dedicated membrane protein machinery to sense and evade attack by antimicrobial peptides. Antimicrobial peptides such as vancomycin are some of the most powerful antibiotics currently in clinical use and are considered a treatment option of last resort. However, infection with Gram-positive organisms such as vancomycin-resistant Enterococcus or Staphylococcus continue to threaten healthcare settings, and leave infected patients with limited treatment options. Many Gram-positive species express membrane protein complexes known as “Bce modules” (BCEMs) that contain an ABC transporter and a two-component system that work in tandem to sense and respond to attack by antimicrobial peptides. Our primary goals are to obtain a complete understanding of how the ABC transporter component of BCEMs recognizes and provides resistance to antimicrobial peptides, and how conformational cycling of the ABC transporter initiates signaling through the two-component system via a flux-sensing mechanism. A comprehensive study of the structure, conformational dynamics, kinetic mechanisms, and in vivo activity of BCEMs will be performed in order to understand how the constituents of these modules work in synergy to sense and respond to antimicrobial peptides. At the culmination of our studies we will have established a structure-driven understanding of the membrane protein complexes that allow Gram-positive pathogens to sense and respond to different antimicrobial peptides. Our long-term vision is to build a comprehensive model of the different protein machineries used by microbial pathogens to circumvent our most powerful antibiotics. Detailed structural and functional analysis of these protein complexes will set the stage for development of new and improved antimicrobial compounds and targeted therapies for drug resistant microbial infections.