A Hitchhiker’s Journey through Machine Learning for Structural Biology of Antibodies

Abstract

This thesis examines the integration of machine learning into computational structural biology, with an emphasis on modelling and predicting antibody–antigen interactions. Such interactions are fundamental to numerous biological processes and are central to therapeutic antibody design. Despite recent advances in AI-based protein structure prediction, antibodies remain particularly challenging targets due to the high variability of their complementarity-determining regions, the limited availability of experimental structures, and the lack of strong co-evolutionary signal. To address these challenges, this work introduces several methodological contributions. In Chapter 2,DeepRank-GNN-esm incorporates embeddings from protein language models to replace computationally expensive evolutionary features, thereby improving both predictive performance and efficiency in scoring protein–protein complexes. In Chapter 3, a modelling pipeline is introduced that employs a flow-matching algorithm to effectively sample the conformational diversity of the antibody CDR-H3 loop. When integrated with ensemble docking, this approach significantly improves the accuracy of antibody–antigen complex modelling compared to existing methods. In Chapter 4, the thesis presents AbTune, a sequence-specific fine-tuning strategy for protein language models that enhances predictive performance across multiple antibody-related tasks, including structure prediction, mutation effect estimation, and binding affinity prediction, while remaining computationally efficient. In Chapter 5, DeepRank-Ab is developed as a geometric deep learning-based scoring function tailored to antibody–antigen complexes, achieving state-of-the-art performance in ranking near-native docking conformations. Chapter 6 summarizes the main findings of the thesis and discusses future research directions. Collectively, these contributions demonstrate how machine learning can be applied to address key limitations in antibody modelling and to facilitate the rational design of antibody-based therapeutics.