Beyond prediction: Why experimental structural biology remains essential in plants.

Structural biology is undergoing a transformative era driven by advances in artificial intelligence (AI)-based protein structure prediction and cryo-electron microscopy. Predictive approaches have dramatically expanded structural coverage across proteomes and are increasingly integrated into experimental workflows. However, protein function frequently depends on dynamic molecular processes including ligand-dependent conformational remodeling, transient interactions, cooperative assembly, and transport-state transitions that remain difficult to define from static computational models alone. These challenges are particularly evident in plants, where signaling pathways often involve environmentally responsive receptor complexes, lineage-expanded regulatory proteins, and transient assemblies. Here, we discuss how experimental structural biology continues to advance plant biology by revealing mechanisms underlying hormone perception, immune receptor activation, transporter function, and enzymatic regulation. From early landmark discoveries such as the crystallization of urease to recent cryo-electron microscopy studies of dynamic signaling complexes, plant systems have repeatedly uncovered molecular architectures, chemically modified intermediates, and regulatory principles that require direct structural and biochemical characterization. Plant proteins also remain markedly underrepresented in structural databases, leaving many plant-specific pathways structurally unresolved. Together, these observations highlight the continuing importance of experimental structural biology for defining biologically relevant molecular states and enabling structure-guided strategies for crop improvement and agricultural biotechnology.