🤖 AI Summary
This study addresses the limitations of existing protein engineering methods, which often neglect structural constraints and suffer from scarce mutant structural data. To overcome these challenges, this work proposes StructEvo, a framework that leverages deep reinforcement learning to integrate structural information for protein sequence optimization. StructEvo introduces an incremental structure-fusion encoder and a hierarchical action network, combining graph neural networks with geometric constraint techniques to effectively decompose the high-dimensional mutation space while enabling precise feature learning and decision-making. Experimental results demonstrate significant performance improvements across multiple benchmarks. Furthermore, the method successfully captures epistatic patterns in green fluorescent protein (GFP), establishing a novel paradigm for structure-aware directed protein evolution.
📝 Abstract
Protein optimization remains a longstanding goal in life sciences. Existing machine learning-assisted directed evolution (MLDE) methods primarily rely on sequence-only features, overlooking the critical spatial constraints and co-evolutionary interactions encoded in protein structures. However, directly integrating structural information remains challenging due to the scarcity of reliable mutant structures. To address these issues, we propose StructEvo, a novel structure-aware reinforcement learning framework for protein directed evolution. StructEvo employs a delta-structure fusion encoder to approximate mutant structure features via feature differences, enabling dynamic incorporation of spatial knowledge. The vast mutation space is then decomposed into manageable subspaces through a structure-aligned hierarchical action network, while a geometric constraint further stabilizes delta feature learning. Our approach outperforms prior state-of-the-art methods by 9.2% and 16.3% on two challenging optimization benchmarks, and further identifies an experimentally validated epistasis pattern in GFP, highlighting the importance of structural guidance for effective protein directed evolution.