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1. Structural and Functional Characterization of European Corn Borer, Ostrinia nubilalis, Pheromone Binding Protein 3

   https://doi.org/10.1021/acs.jafc.1c03775  

   Omar Al-Danoon, Suman Mazumder (January 2021, Journal of agricultural and food chemistry)

   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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2. Heterologous expression, structural analysis, and functional characterization of Ostrinia nubilalis pheromone-binding protein 2 (OnubPBP2)

   https://doi.org/10.1038/s41598-026-43384-0  

   Nukala, Viswanath; Al-Danoon, Omar; Mohanty, Smita (March 2026, Scientific Reports)

   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. 

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3. Disrupting Pheromone Signaling in Insects: Design, Synthesis, and Evaluation of an Inhibitor

   https://doi.org/10.1021/acsomega.5c06376  

   Paudel, Pratikshya; Ray, Ishani; Al_Danoon, Omar; Howard, James R; Maier, Josef M; Moor, Sarah R; Lidskog, Anna M; Anslyn, Eric V; Mohanty, Smita (March 2026, ACS Omega)

   Sex pheromones mediate mate recognition in insects through interactions with pheromone-binding proteins (PBPs). Targeting this pathway with pheromone analogs offers a species-specific approach to pest management. Here, we report the design, synthesis, and evaluation of a pheromone analog, (6E,11Z)-heptadeca-6,11-dien-1-yl acetate, as an inhibitor of Antheraea polyphemus PBP1 (ApolPBP1). Molecular docking predicted potential binding orientations and interactions within the pocket. Fluorescence-based binding assays revealed a four-fold higher dissociation constant, and 2D [¹H, ¹⁵N] HSQC NMR titrations confirmed reduced affinity, with ApolPBP1 transitioning to the bound state only at higher analog concentrations. Overall, these findings highlight the sensitivity of PBPs to subtle structural modifications in their ligands and emphasize the importance of preserving key molecular interactions for effective binding. 

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4. 1H, 15N and 13C resonance assignments for free and IEEVD peptide-bound forms of the tetratricopeptide repeat domain from the human E3 ubiquitin ligase CHIP

   https://doi.org/10.1007/s12104-016-9710-y  

   Zhang, Huaqun; McGlone, Cameron; Mannion, Matthew M.; Page, Richard C. (October 2016, Biomolecular NMR Assignments)

   The ubiquitin ligase CHIP catalyzes covalent attachment of ubiquitin to unfolded proteins chaperoned by the heat shock proteins Hsp70/Hsc70 and Hsp90. CHIP interacts with Hsp70/Hsc70 and Hsp90 by binding of a C-terminal IEEVD motif found in Hsp70/Hsc70 and Hsp90 to the tetratricopeptide repeat (TPR) domain of CHIP. Although recruitment of heat shock proteins to CHIP via interaction with the CHIP-TPR domain is well established, alterations in structure and dynamics of CHIP upon binding are not well understood. In particular, the absence of a structure for CHIP-TPR in the free form presents a significant limitation upon studies seeking to rationally design inhibitors that may disrupt interactions between CHIP and heat shock proteins. Here we report the 1H, 13C, and 15N backbone and side chain chemical shift assignments for CHIP-TPR in the free form, and backbone chemical shift assignments for CHIP-TPR in the IEEVD-bound form. The NMR resonance assignments will enable further studies examining the roles of dynamics and structure in regulating interactions between CHIP and the heat shock proteins Hsp70/Hsc70 and Hsp90. 

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5. Pheromone-Binding Proteins in Pest Control: From Molecular Insights to Real-World Applications

   https://doi.org/10.1021/acs.jafc.5c03663  

   Ray, Ishani; Mohanty, Smita (September 2025, Journal of Agricultural and Food Chemistry)

   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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