Collaborative Research: Investigating the Interplay between the Conformational and Functional Space of Membrane Proteins and the Physicochemical Properties of the Surrounding Bilay

生物膜及其成分几乎参与了对生物体至关重要的所有过程，包括免疫反应。本研究探讨了几种免疫反应因子如何通过在细菌细胞膜上相互作用来结合它们的抗菌作用。感兴趣的具体药物是宿主防御肽和铜离子。宿主防御肽是一种作用于多种致病细胞（包括细菌、病毒和真菌）的强大分子。存在于免疫细胞中的铜离子可以通过氧化细菌的磷脂来破坏细菌的细胞膜。有趣的是，一些宿主防御肽含有一个铜结合基序，使它们能够结合铜并成为金属肽。在这个项目中，pi将开发新的生物物理和生化工具来研究宿主防御金属肽和铜离子如何协同它们的抗菌作用。这个项目有可能产生新的原理，可以用于设计新的抗菌生物材料。此外，该项目还将包括一些活动，让来自不同背景的大学生和预科生参与动手科学，提高他们的分析能力。pi将利用他们研究的跨学科和合作性质，以及对科学研究的热情来激发年轻学生的科学兴趣，并为高中生成功过渡到大学做好准备。本研究的主要目的是对生物膜上宿主防御机制之间的相互作用进行严格的研究。感兴趣的分子系统是膜相互作用的宿主防御金属肽和其他免疫反应剂，它们有可能在脂质膜上统一它们的抗菌作用。虽然宿主防御肽已被研究其破坏细菌细胞膜构象排列的能力，但宿主防御肽和其他免疫因子（如铜和氧化脂质）协同其抗菌作用的可能性尚未在分子水平上探索。pi将使用来自鱼（piscidins）和蜱（ixosins）的肽来验证这一假设。他们将利用他们在膜组件表征方面的专业知识，利用尖端生物物理技术（固态核磁共振、中子衍射、表面敏感方法）和生物分析的平台，在类似天然条件下获得这些金属肽的结构-动力学-功能信息。该项目将专注于模型膜，以准确和精确地控制膜的组成，并直接将其分子含量与宿主防御金属肽的特定功能和构象行为及其与双层的相互作用联系起来。该项目将对与所选宿主防御肽的生物学背景相关的活细胞进行分析，以研究脂质氧化对肽的抗菌效力的贡献，确定肽之间的协同效应，并将生物效力与物理化学性质联系起来。该项目将产生多方面的广泛影响。首先，新发现和新方法将有助于推进膜生物物理学、结构生物学、免疫学和生物化学等领域的科学知识。这些基本原理可用于设计新型抗菌剂和生物材料。第二，科学环境将促进学术界和国家实验室之间的伙伴关系。第三，拓展活动将激发来自不同背景的大学生和预科生对动手科学的兴趣，并提高他们的分析能力。

Biological membranes and their constituents are involved in virtually all processes vital to living organisms, including the immune response. This research investigates how several agents of the immune response combine their antimicrobial effects by interacting with each other on bacterial cell membranes. The specific agents of interest are host defense peptides and copper ions. Host defense peptides are powerful molecules that act on a broad range of pathogenic cells, including bacteria, viruses, and fungi. Copper ions, which are present in immune cells, can damage the cell membranes of bacteria by oxidizing their phospholipids. Interestingly, some host-defense peptides contain a copper-binding motif that enables them to bind copper and become metallopeptides. In this project, the PIs will develop new bio-physical and biochemical tools to investigate how host defense metallopeptides and copper ions may synergize their antimicrobial effects. This project has the potential to produce new principles that could be useful to design novel antimicrobial biomaterials. In addition, the project will include activities that engage college and pre-college students from diverse backgrounds in hands-on science and enhance their analytical skills. The PIs will leverage the interdisciplinary and collaborative nature of their research, and passion for scientific research to spike scientific interest in young students and prepare high school students for a successful transition to college. The major goal of this research is a rigorous investigation of the interplay between host defense mechanisms at biological membranes. The molecular systems of interest are membrane-interacting host defense metallopeptides and other agents of the immune response that have the potential to unify their antimicrobial effects at lipid membranes. While host defense peptides have been studied for their ability to disrupt the conformational arrangement in bacterial cell membranes, the possibility that host defense peptides and other immune agents such as copper and oxidized lipids synergize their antimicrobial effects has not been explored on a molecular level. The PIs will test this hypothesis using peptides from fish (piscidins) and ticks (ixosins). They will leverage their expertise in the characterization of membrane assemblies and harness a platform of cutting-edge biophysical techniques (solid-state NMR, neutron diffraction, surface-sensitive methods) and biological assays to obtain structure-dynamics-function information on these metallopeptides under native-like conditions. The project will focus on model membranes to accurately and precisely control membrane composition and directly relate their molecular contents to specific functional and conformational behaviors of host defense metallopeptides and their interactions with bilayers. The project will feature assays on live cells relevant to the biological context of the chosen host defense peptides to investigate the contribution of lipid oxidation to the antimicrobial potency of the peptides, identify synergistic effects among peptides, and relate biological potencies to physicochemical properties. This project will generate multiple broad impact outcomes. First, the new findings and methodologies created will contribute to advancing scientific knowledge in the fields of membrane biophysics, structural biology, immunology, and biochemistry. These fundamental principles could be useful to design novel antimicrobial agents and biomaterials. Second, the scientific environment will foster partnerships between academia and national labs. Third, the outreach activities will stimulate the interest of college and pre-college students from diverse backgrounds in hands-on science, and enhance their analytical skills.