The western corn rootworm (Diabrotica virgifera virgifera) relies on odorant-binding proteins (OBPs) to locate maize hosts and mates via volatile organic compounds (VOCs). However, the molecular recognition mechanisms of specific attractants, such as (E)-β-caryophyllene, 6-methoxy−2-benzoxazolinone (6-MBOA), and the sex pheromone 8R-methyl−2R-decyl propanoate (2R,8R-MDP), remain elusive. Here, we integrated phylogenetic analysis, AlphaFold2 structural prediction, molecular docking, molecular dynamics (MD) simulations, and in vitro fluorescence competitive binding assays to characterize the binding specificity of DvirOBPs toward these key ligands. Pan-family screening identified DvirOBP54b as possessing the highest ligand-binding specificity, resolving its evolutionary divergence from its tandem duplicative paralog DvirOBP54a. Structural and dynamic analyses revealed that DvirOBP54b binding to (E)-β-caryophyllene and 2R,8R-MDP is predominantly driven by hydrophobic interactions within a core pocket (Phe7, Phe69, Ile70, Ala121). Conversely, its interaction with 6-MBOA is further stabilized by a specific hydrogen bond at Thr66. Dynamic trajectories confirmed the high stability of the DvirOBP54b complexes, while in vitro assays validated the strong binding affinities toward the core host-derived volatiles. These findings elucidate the structural basis of VOC-mediated olfactory recognition in D. v. virgifera, providing critical molecular targets for developing high-efficiency attractants and novel pest management strategies.
Zhao et al. (Fri,) studied this question.