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Ostrinia nubilalis, a lepidopteran moth, also known as the European corn borer, has a major impact on the production of economically important crops in the United States and Europe. The female moth invites the male moth for mating through the release of pheromones, a volatile chemical signal. Pheromone binding proteins (PBPs) present in the male moth antennae are believed to pick up the pheromones, transport them across the aqueous sensillum lymph, and deliver them to the olfactory receptor neurons. Here we report for the first time the cloning, expression, refolding, purification, and structural characterization of Ostrinia nubilalis PBP3 (OnubPBP3). The recombinant protein showed nanomolar affinity to each isomer of the Ostrinia pheromones, E- and Z-11-tetradecenyl acetate. In a pH titration study by nuclear magnetic resonance, the protein exhibited an acid-induced unfolding at pH below 5.5. The molecular dynamics simulation study demonstrated ligand-induced conformational changes in the protein with both E- and Z-isomers of the Ostrinia pheromone. The simulation studies showed that while protein flexibility decreases upon binding to E-pheromone, it increases when bound to Z-pheromone. This finding suggests that the OnubPBP3 complex with E-pheromone is more stable than with Z-pheromone.
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Pheromone-Binding Proteins in Pest Control: From Molecular Insights to Real-World Applications
Insects utilize sophisticated olfactory systems to detect chemical cues critical for behaviors such as mating, host selection, and predator avoidance. In lepidopteran moths, sex pheromone communication offers a well-established model where males detect female-emitted signals over long distances. Central to this process are pheromone-binding proteins (PBPs), which solubilize and transport hydrophobic pheromones through the sensillar lymph to olfactory receptors, enabling precise signal detection. Recent advances in molecular biology, structural biochemistry, and gene-editing technologies such as CRISPR/Cas9 have uncovered nuanced mechanisms underlying PBP function, including ligand-binding specificity, pH-dependent conformational dynamics, and molecular interactions. These discoveries have broad implications, extending beyond chemosensory biology to applications in reverse chemical ecology, biosensing, and environmentally conscious pest control. This review synthesizes insights from in vitro, in silico, and in vivo studies, highlighting the structural and functional diversity of PBPs across species and emphasizing their translational utility as molecular targets for sustainable agriculture and biodiversity conservation.
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- Award ID(s):
- 2402694
- PAR ID:
- 10671862
- Publisher / Repository:
- American Chemical Society
- Date Published:
- Journal Name:
- Journal of Agricultural and Food Chemistry
- Volume:
- 73
- Issue:
- 35
- ISSN:
- 0021-8561
- Page Range / eLocation ID:
- 21701 to 21727
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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The European corn borer (Ostrinia nubilalis) is a major lepidopteran pest, causing annual maize losses of 5.5–8.5 million tons worldwide. Successful mating relies on the male’s ability to detect species-specific, hydrophobic sex pheromones released by females. Pheromone-binding proteins (PBPs), abundantly expressed in male antennae, capture these pheromones and transport them through the sensillar lymph to olfactory receptor neurons. Here, we report the first successful heterologous expression, purification, and functional characterization of O. nubilalis PBP2 (OnubPBP2). Fluorescence binding assays show that recombinant OnubPBP2 is active and binds both E- and Z-isomers of 11-tetradecenyl acetate with nanomolar affinity at pH 6.5. The calculated binding energies based on molecular docking simulation are in good agreement with the binding affinities measured using fluorescence displacement assays. High-resolution NMR titrations reveal a reversible pH-dependent conformational transition, with OnubPBP2 adopting a partially unfolded, molten-globule-like state under acidic conditions. Such conformational flexibility, observed across several Ostrinia PBPs, likely represents an adaptive mechanism that balances structural stability with ligand release efficiency, defining a divergent PBP subclass with unique pH-dependent dynamics likely contributing to enhanced functional versatility.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1021/acs.jafc.5c03663
