增强的采样方法,如元吸附和伞采样已成为探索分子和材料的配置空间的重要工具。与此同时,他们长期以来一直面临着一些问题,如处理大量集体变量(CV)或具有高自由能势垒的系统时的效率低下。在这项工作中,我们表明,与\redc{the clustering and adaptive tuning techniques},增强动力学(RiD)计划可以用来有效地探索配置空间和自由能景观与大量的CV或系统具有高自由能障碍。我们通过研究各种具有代表性和挑战性的例子来说明这一点。首先,我们证明了自适应RiD与其他方法相比的效率,并构建了9维自由能景观的类肽三聚体,具有超过8千卡/摩尔的能量障碍。然后,我们使用18个CV研究了蛋白质chignolin的折叠。在这种情况下,观察到折叠和解折叠速率均等于4.30~ $μs^{-1}$。最后,我们提出了一个基于RiD的蛋白质结构精化协议。该协议允许我们有效地使用100多个CV来探索蛋白质结构的景观,并且它比初始的全局距离测试-高准确度(GDT-HA)分数整体提高了14.6个单位。
英文摘要:
Enhanced sampling methods such as metadynamics and umbrella sampling have become essential tools for exploring the configuration space of molecules and materials. At the same time, they have long faced a number of issues such as the inefficiency when dealing with a large number of collective variables (CVs) or systems with high free energy barriers. In this work, we show that with \redc{the clustering and adaptive tuning techniques}, the reinforced dynamics (RiD) scheme can be used to efficiently explore the configuration space and free energy landscapes with a large number of CVs or systems with high free energy barriers. We illustrate this by studying various representative and challenging examples. Firstly we demonstrate the efficiency of adaptive RiD compared with other methods, and construct the 9-dimensional free energy landscape of peptoid trimer which has energy barriers of more than 8 kcal/mol. We then study the folding of the protein chignolin using 18 CVs. In this case, both the folding and unfolding rates are observed to be equal to 4.30~$μs^{-1}$. Finally, we propose a protein structure refinement protocol based on RiD. This protocol allows us to efficiently employ more than 100 CVs for exploring the landscape of protein structures and it gives rise to an overall improvement of 14.6 units over the initial Global Distance Test-High Accuracy (GDT-HA) score.
Reinforced dynamics for enhanced sampling in large atomic and molecular systems
Princeton University(普林斯顿大学);Institute of Applied Physics and Computational Mathematics(应用物理与计算数学研究所);CAEP Software Center for High Performance Numerical Simulation(中国工程物理研究院高性能数值模拟软件中心);Beijing Institute of Big Data Research(北京大数据研究院)
Fast and Flexible Geometric Method For Enhancing MC Sampling of Compact Configurations For Protein Docking Problem
EASAL(Efficient Extracasing and Sampling of Assembly Landscapes)是一种几何方法,用于对小分子组装体的势能景观进行采样和计算积分。EASAL的效率源于这样一个事实,即小装配景观允许使用所谓的凯莱(原子间距离为基础)参数的几何表示和采样的装配配置空间区域;这导致他们的隔离,凸化,定制采样和系统遍历使用一个全面的拓扑路线图。我们定义定制设计的测量,调查和比较各种采样特性的EASAL和传统的蒙特卡罗(MC)采样,包括(i)采样速度,(ii)效率和均匀网格覆盖的准确性,(iii)覆盖低能量区域的加权覆盖的准确性,(iv)本地化采样到宏观状态的能力,和(v)采样分布的灵活性。特别是,我们比较了EASAL和MC的采样特性,在采样的装配景观的2个跨膜螺旋,与短程对电位。我们证明,EASAL提供了一个合理的覆盖率的关键,但狭窄的区域的能源景观的低有效尺寸,少得多的样本和计算资源比MC采样。结合这两种方法的互补优势的有前途的途径进行了讨论。
Best of Both Worlds: Uniform sampling in Cartesian and Cayley Molecular Assembly Configuration Space
EASAL(efficient atlasing and sampling of assembly landscape)是一种用于表征、可视化、采样和计算小分子组装势能面积分的几何方法。EASAL的效率来自于这样一个事实,即小装配景观允许使用所谓的凯莱参数(原子间距离)的几何表示和采样的装配配置空间区域;这导致他们的隔离,凸化,定制采样和系统遍历使用一个全面的拓扑路线图,确保合理覆盖的关键,但狭窄的区域低有效尺寸。然而,这本身是不够的构型熵和其他积分的准确计算,需要估计的自由能和动力学-其中,它是必不可少的,以获得均匀的采样在适当的carnival或模空间参数化。通过两个参数化之间的映射的雅可比矩阵对凯莱采样进行标准调整充满了来自病态雅可比矩阵的挑战。本文形式化和分析这些挑战,提供修改EASAL,确保凯莱采样的优势,同时确保一定的最小距离和覆盖范围之间的关系采样配置-在笛卡尔空间。将修饰的EASAL的性能与基本EASAL进行比较,并提供了人和大鼠胰岛淀粉样多肽(HiAPP、PDB-2KJ 7和RiAPP PDB-2KB 8)二聚化的数据(两者仅在37个残基中的6个残基上不同,但前者聚集成原纤维,而后者不)。
Energy-Guided Generative Modeling for Low-Energy Molecular Structure Discovery
School of Artificial Intelligence, Shanghai Jiao Tong University(上海交通大学人工智能学院);Department of Computer Science, National University of Singapore(新加坡国立大学计算机科学系);Shenzhen International Graduate School, Tsinghua University(清华大学深圳国际研究生院)
Hamiltonian replica exchange augmented with diffusion-based generative models and importance sampling to assess biomolecular conformational basins and barriers