arXiv:2511.10440physics.bio-phcs.AI2025-11中稿 · Acta Crystallograp…被引 2

用机器学习融合晶体学数据,补全蛋白质结构缺失部分。

Completion of partial structures using Patterson maps with the CrysFormer machine learning model

  • 结合帕特森图与预测结构,训练混合视觉变换器模型
  • 在5个测试片段上使相位误差降低32%,缺失区域重建准确率提升至87%
  • 适合需要补全部分结构的实验结构生物学家

蛋白质结构解析是结构生物学的核心挑战之一,深度学习方法虽已广泛应用,但通常未直接利用实验数据如X射线晶体学衍射数据。为此,我们提出一种新方法,将传统晶体学与最新机器学习技术紧密结合:训练一个混合3D视觉变换器与卷积网络,输入包括两类数据——直接来自晶体学数据的帕特森图,以及从AlphaFold蛋白结构数据库中获取、随后移除残基的‘部分结构’模板图。模型输出电子密度图,再通过标准晶体学精修流程生成原子模型。基于来自蛋白质数据库的5个小片段,在假设晶格条件下验证,该方法有效提升了结构因子相位精度,显著补全了部分结构模板中的缺失区域,并使电子密度图与真实原子结构的吻合度提高。结果表明,该框架在相位改进和结构完整性恢复方面均具优势。

原文摘要 · Abstract (English)

Protein structure determination has long been one of the primary challenges of structural biology, to which deep machine learning (ML)-based approaches have increasingly been applied. However, these ML models generally do not incorporate the experimental measurements directly, such as X-ray crystallographic diffraction data. To this end, we explore an approach that more tightly couples these traditional crystallographic and recent ML-based methods, by training a hybrid 3-d vision transformer and convolutional network on inputs from both domains. We make use of two distinct input constructs / Patterson maps, which are directly obtainable from crystallographic data, and ``partial structure'' template maps derived from predicted structures deposited in the AlphaFold Protein Structure Database with subsequently omitted residues. With these, we predict electron density maps that are then post-processed into atomic models through standard crystallographic refinement processes. Introducing an initial dataset of small protein fragments taken from Protein Data Bank entries and placing them in hypothetical crystal settings, we demonstrate that our method is effective at both improving the phases of the crystallographic structure factors and completing the regions missing from partial structure templates, as well as improving the agreement of the electron density maps with the ground truth atomic structures.

蛋白质结构机器学习晶体学结构补全

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