NANOSCALE: Structural Changes in Fibronectin Binding Domains upon Adsorption to Well-Defined Surface Chemistries

细胞与吸附在材料表面上的蛋白质的粘附对于许多生物医学和生物技术应用是至关重要的，包括生物材料、组织工程和体外细胞培养系统。 细胞与细胞外蛋白的附着主要由细胞表面受体的整联蛋白家族介导。 整合素与细胞外基质组分中的特定氨基酸序列结合。 例如，整联蛋白a5 b1结合纤连蛋白（Fn）中的PHSRN和RGD结构域。 这种相互作用是由这两个域的相对结构取向控制的，这两个域相距3-4 nm。 每个结构域独立地对结合贡献很小，但是在组合中，它们协同地结合到受体以产生粘附的显著增加。 此外，吸附到表面后，Fn发生结构变化，改变了a5 b1结合，表明这些结合结构域的相对取向发生了变化。（FnIII 7 -10），其含有PHSRN和RGD结合位点，到呈现良好定义的表面化学的烷硫醇的自组装单层上（CH 3、NH 2、COOH和OH）。 具体而言，创新的实验和计算方法被集成到模型中的PHSRN和RGD域的相对方向的变化和这些结构变化和整合素结合之间的关系。 首先，吸附的FnIII 7 -10的构象将使用单克隆抗体和从分子模拟获得的结构和热力学信息进行表征。 然后将分析整合素a5 b1与吸附的FnIII 7 -10的功能结合，其特征在于粘附强度和相对结合亲和力，并与结构参数相关。 通过整合实验和计算的方法，这种分析将提供一个机制的理解蛋白质表面的相互作用和吸附诱导的结构变化在蛋白质功能中的作用。 最后，拟议的研究将提供一个分析框架，适用于其他蛋白质/表面

Cell adhesion to proteins adsorbed onto material surfaces is critical to numerous biomedical and biotechnological applications, including biomaterials, tissue engineering, and in vitro cell culture systems. Cell attachment to extracellular proteins is primarily mediated by the integrin family of cell surface receptors. Integrins bind to specific amino acid sequences in extracellular matrix components. For example, integrin a5b1 binds to the PHSRN and RGD domains in fibronectin (Fn). This interaction is controlled by the relative structural orientation of these two domains, which are 3-4 nm apart. Each domain independently contributes little to binding, but in combination, they synergistically bind to the receptor to produce significant increases in adhesion. Moreover, upon adsorption to surfaces, Fn undergoes structural changes that modify a5b1 binding, suggesting changes in the relative orientation of these binding domains.This project focuses on modeling the adsorption of a well-characterized fragment of Fn (FnIII7-10), which contains the PHSRN and RGD binding sites, onto self-assembled monolayers of alkanethiols presenting well-defined surface chemistries (CH3, NH2, COOH, and OH). Specifically, innovative experimental and computational approaches are integrated to model changes in the relative orientation of the PHSRN and RGD domains and the relationship between these structural changes and integrin binding. First, the conformation of adsorbed FnIII7-10 will be characterized using monoclonal antibodies and structural and thermodynamic information obtained from molecular simulations. The functional binding of integrin a5b1 to adsorbed FnIII7-10, characterized by adhesion strength and relative binding affinity, will then be analyzed and correlated to the structural parameters. By integrating experimental and computational approaches, this analysis will provide a mechanistic understanding of protein-surface interactions and the role of adsorption-induced structural changes in protein function. Finally, the proposed research will provide an analytical framework that is applicable to other protein/surface