arXiv:2508.00578cs.LGcond-mat.mtrl-sci2025-08

用机器学习势能面模拟肽类氢原子转移反应,实现量子精度预测反应能垒。

Learning Potential Energy Surfaces of Hydrogen Atom Transfer Reactions in Peptides

  • 构建肽类氢原子转移构型数据集,训练图神经网络模型学习势能面。
  • MACE模型在未见数据上预测能垒误差仅1.13 kcal/mol,性能最优。
  • 可推广至胶原蛋白等复杂体系,助力生物分子反应机理研究。

氢原子转移(HAT)反应在蛋白质损伤后的自由基迁移等生物过程中至关重要,但其机制路径仍不明确。由于需在生物尺度上保持量子化学精度,传统经典力场和基于DFT的分子动力学均难以适用。机器学习势能面可实现近量子精度建模,但要在多种HAT构型(尤其蛋白质中的自由基位点)上良好泛化,需定制化数据生成与模型选择。本文系统构建肽类HAT构型数据集,采用半经验方法与DFT生成大规模数据,并对比SchNet、Allegro与MACE三种图神经网络在学习HAT势能面及间接预测反应能垒方面的表现。结果显示,MACE在能量、力与能垒预测上始终领先,在分布外的DFT能垒预测中均方误差仅为1.13 kcal/mol。分子动力学模拟表明,该模型具有稳定性、反应性且可超越训练数据泛化至胶原蛋白I,实现高精度反应能垒预测。此精度使机器学习势能面可用于大尺度胶原蛋白模拟,结合能垒计算反应速率,推动对肽类中氢原子转移与自由基迁移机制的理解。我们进一步分析了缩放规律、模型迁移性与性价比权衡,并提出结合过渡态搜索与主动学习以提升模型性能。本方法具有普适性,适用于其他生物分子体系,实现复杂环境中化学反应性的量子精确模拟。

原文摘要 · Abstract (English)

Hydrogen atom transfer (HAT) reactions are essential in many biological processes, such as radical migration in damaged proteins, but their mechanistic pathways remain incompletely understood. Simulating HAT is challenging due to the need for quantum chemical accuracy at biologically relevant scales; thus, neither classical force fields nor DFT-based molecular dynamics are applicable. Machine-learned potentials offer an alternative, able to learn potential energy surfaces (PESs) with near-quantum accuracy. However, training these models to generalize across diverse HAT configurations, especially at radical positions in proteins, requires tailored data generation and careful model selection. Here, we systematically generate HAT configurations in peptides to build large datasets using semiempirical methods and DFT. We benchmark three graph neural network architectures (SchNet, Allegro, and MACE) on their ability to learn HAT PESs and indirectly predict reaction barriers from energy predictions. MACE consistently outperforms the others in energy, force, and barrier prediction, achieving a mean absolute error of 1.13 kcal/mol on out-of-distribution DFT barrier predictions. Using molecular dynamics, we show our MACE potential is stable, reactive, and generalizes beyond training data to model HAT barriers in collagen I. This accuracy enables integration of ML potentials into large-scale collagen simulations to compute reaction rates from predicted barriers, advancing mechanistic understanding of HAT and radical migration in peptides. We analyze scaling laws, model transferability, and cost-performance trade-offs, and outline strategies for improvement by combining ML potentials with transition state search algorithms and active learning. Our approach is generalizable to other biomolecular systems, enabling quantum-accurate simulations of chemical reactivity in complex environments.

机器学习势能面自由基反应肽类模拟

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