New approaches to reveal quantitative free energy landscapes in molecular interactions by single molecule force spectroscopy

提出了用于执行和分析单分子力测量的新方法，并将其应用于分子间（例如蛋白质-配体或金属螯合络合物）和分子内相互作用，如在蛋白质折叠和展开过程中观察到的。这两个，数据分析程序和现有的设计力光谱实验的分子间测量将得到改善。具体地，这里需要允许在同一个分子上无限制地重复实验，以避免源自牵拉方向和表面之间的不受控制的角度以及非特异性和多重相互作用的伪影。所应用的策略克服了现有的实验障碍，通过设计的聚合物支架上的相互作用伙伴可以具体绑定在一个定义的几何形状。在我们的小组中开发的数据分析程序，这给力依赖的解离率将得到改进，包括复杂的自由能景观，显示出曲率和粗糙度周围的约束和过渡态。力依赖的自由活化能和指数前置因子在Arkalius方程将获得从温度依赖的力测量。严格的统计误差分析的实验结果将允许定量模型测试的自由能景观。

New approaches for performing and analysing single molecule force measurements are proposed and will be applied to intermolecular (e.g. protein-ligand or metal chelating complexes) and to intramolecular interactions as observed in protein folding and unfolding processes. Both, the data analysis procedures and the existing design of force spectroscopic experiments for intermolecular measurements will be improved. Specifically, here it is required to allow for unlimited repetition of the experiment on one and the same molecule to avoid artefacts originating from an uncontrolled angle between pulling direction and surface as well as unspecific and multiple interactions. The strategy applied overcomes the existing experimental obstacles by the design of a polymer scaffold on which the interaction partners can be specifically bound in a defined geometry. The data analysis procedures developed in our group, which give force dependent off-rates will be improved to include complex free energy landscapes which show a curvature and roughness around the bound and the transition state. Force dependent free activation energies and exponential prefactors in the Arrhenius equation will be obtained from temperature dependent force measurements. Rigorous statistical error analysis of the experimental results will allow for quantitative model testing for free energy landscapes.