Theoretical & Computational Biophysics, MPI for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
Phys Rev Lett. 2012 Sep 14;109(11):118304. doi: 10.1103/PhysRevLett.109.118304.
Experimental and computational dynamic force spectroscopy is widely used to determine the mechanical properties of single biomolecules. Whereas so far the focus has mainly been on rupture or unfolding forces, recent force-probe molecular dynamics simulations have revealed a strong loading rate dependence of biomolecular elasticities, which cannot be explained by the established one-dimensional transition-state treatments. We show that this nonequilibrium behavior can be explained by a theory that includes relaxation effects. For three structurally and mechanically quite diverse systems, a single relaxation mode suffices to quantitatively describe their loading-rate-dependent elastic behavior. Atomistic simulations of these systems revealed the microscopic nature of the respective relaxation modes. This result suggests a new type of "elasticity spectroscopy" experiment, which should render nonequilibrium properties of structured macromolecules accessible to single-molecule force spectroscopy.
实验和计算动力学力谱广泛用于测定单生物分子的机械性能。尽管到目前为止，研究的重点主要集中在断裂或展开力上，但最近的力探针分子动力学模拟揭示了生物分子弹性对加载速率的强烈依赖性，这不能用已建立的一维过渡态处理来解释。我们表明，这种非平衡行为可以用一种包括弛豫效应的理论来解释。对于三个结构和力学上非常不同的系统，单个弛豫模式足以定量描述它们的加载速率依赖性弹性行为。这些系统的原子模拟揭示了各自弛豫模式的微观性质。这一结果表明了一种新的“弹性光谱”实验类型，它应该使结构大分子的非平衡性质能够通过单分子力谱来测量。
