Geometry-Aware Line Graph Transformer Pretraining for Molecular Property Prediction.

Bai, Peizhen; Liu, Xianyuan; Fan, Wenrui; Jiang, Tianyi; Cheung, William K; Lu, Haiping · IEEE Trans Neural Netw Learn Syst · 2026

basic_science · Level V

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Abstract

Molecular property prediction with deep learning approaches has gained much attention over the past years. Due to the scarcity of labeled molecules, there has been growing interest in self-supervised learning (SSL) methods that learn generalizable molecular representations from unlabeled data through pretraining. Molecules are typically modeled as 2-D topological graphs. However, their 3-D geometry is also important in determining molecular functionalities, and such 3-D information can enhance 2-D molecular representation learning. The 2-D-3-D pretraining has two key challenges: 1) how to construct a high-capacity backbone network to encode the dual-modality molecular information and 2) how to design effective pretraining tasks to learn both intermodality and intramodality relations simultaneously. To tackle these two challenges, we propose a Geometry-aware line graph transformer (Galformer) pretraining framework, a novel SSL method that aims to enhance molecular representation learning from a dual-modality perspective. Specifically, we first design a dual-modality line graph transformer backbone to adaptively encode a molecule's 2-D topological and 3-D geometric line graphs. The designed backbone has a high capacity and can capture critical structural information from both 2-D and 3-D modalities. Then, we devise two complementary pretraining tasks to achieve a comprehensive understanding at both intermodality and intramodality levels. These tasks provide properly supervised information and effectively extract discriminative 2-D and 3-D knowledge from unlabeled molecules. We evaluate Galformer against ten state-of-the-art baselines on 15 property prediction benchmarks via downstream fine-tuning. The experimental results show that Galformer consistently outperforms all baselines on both classification and regression tasks, demonstrating its effectiveness. Our source code is available at GitHub: https://github.com/peizhenbai/Galformer.