Understanding how the S. Epidermidis Biofilm Proteins Aap and AtlE Interact with Surfaces

生物膜形成的第一步是细菌附着到表面。这种依恋是由 细胞表面上的组件以及表面本身。了解所涉及的化学相互作用 依恋是预防生物膜相关疾病的重要组成部分。有几种蛋白质被认为与 细菌附着和生物膜的启动，但它们在表面的行为却鲜为人知。此外，几乎没有人 存在能够表征表面结合蛋白质行为的实验技术。这个项目 目的：研究表皮链球菌生物膜相关蛋白AAP和ATLE的性质。 与曲面交互。最近发展起来的利用核磁共振波谱的方法将被用来研究 这些蛋白质在不同的纳米颗粒表面的结构和取向。纳米颗粒提供了一种重要的 与宏观表面相比，表面与体积的比率增加，最近的证据表明 纳米粒子的曲率不会实质上改变蛋白质-表面相互作用的性质。这使得 纳米粒子是研究蛋白质表面相互作用的一个有吸引力的系统.这项工作使用的是纳米颗粒 用于模拟由玻璃和塑料制成的表面，通常用于植入式医疗器械的表面，如 以及暴露于宿主细胞外基质蛋白的表面。提出了三个具体目标：(1) 基于核磁共振确定生物膜相关蛋白质与表面相互作用的结构模式 氢-氚交换、化学标记和弛豫测量将应用于AAP和 绑定到曲面的Atle域。(2)了解生物膜蛋白质竞争如何影响表面 结合，将研究AAP和ATLE结构域的混合物，监测真实的同时表面结合 时间到了。(3)为了确定生物膜蛋白质如何结合到化学钝化的表面，我们将探索 AAP和ATLE结构域的蛋白质性质(如电荷、大小)调节与涂层表面的结合 佩格和吐温-20。用聚乙二醇治疗是减少蛋白质结合的一种常见策略，但这不是 完全阻止约束，原因尚不清楚。生物膜是医院的一个主要原因- 美国的相关感染，这个项目将使我们更好地了解艾滋病的早期阶段 细菌附着。该项目应用新颖和创新的技术来研究化学基础 对AAP和ATLE的吸附，其结果也将直接与其他细菌生物膜相关。这个 这项研究揭示的机制细节将有助于理解生物膜是如何形成的，以及这样的见解 最终可能导致更好的方法来抑制表面生物膜的形成。

The first step in biofilm formation is bacterial attachment to a surface. This attachment is mediated by components on the cell surface as well as the surface itself. Understanding the chemical interactions involved in attachment is an important part of preventing biofilm-related illness. Several proteins have been implicated in bacterial attachment and biofilm initiation, but their behavior on surfaces is poorly understood. Moreover, few experimental techniques exist that are able to characterize surface-bound protein behavior. This project investigates the properties of two biofilm-related proteins in Streptococcus epidermidis, Aap and AtlE, as they interact with surfaces. Recently developed approaches using NMR spectroscopy will be employed to study the structure and orientation of these proteins on various nanoparticle surfaces. Nanoparticles offer a significant increase in surface to volume ratio compared to macroscopic surfaces, and recent evidence suggests that nanoparticle curvature does not substantially alter the nature of protein-surface interactions. This makes nanoparticles an attractive system for studying protein surface interactions. This work uses nanoparticles are used to model surfaces made of glass and plastic, surfaces commonly used in implanted medical devices, as well as surfaces exposed to host extracellular matrix proteins. Three specific aims are proposed: (1) To identify the structural mode of interaction between biofilm-related proteins and surfaces, NMR-based hydrogen deuterium exchange, chemical labeling, and relaxation measurements will be applied to Aap and AtlE domains bound to surfaces. (2) To understand how biofilm protein competition influences surface binding, mixtures of Aap and AtlE domains will be studied, monitoring simultaneous surface binding in real time. (3) To determine how biofilm proteins bind to chemically passivated surfaces, we will explore the protein properties (e.g. charge, size) of Aap and AtlE domains that modulate binding to surfaces coated with PEG and Tween-20. Treatment with PEG is a common strategy for reducing protein binding, but this does not prevent binding entirely, and the reason why is not clear. Biofilms represent a major cause of hospital- associated infection in the US, and this project will lead to a better understanding of the early stages of bacterial attachment. This project applies novel and innovative techniques to study the chemical basis of adsorption of Aap and AtlE, and the results will be directly relevant to other bacterial biofilms as well. The mechanistic details revealed by this study will be useful in understanding how biofilms form, and such insights could ultimately lead to better approaches for inhibiting the formation of biofilms on surfaces.