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Ostrinia furnacalis, a lepidopteran moth, is an invasive pest found in Asia, Australia, Africa and parts of the United States. The Ostrinia furnacalis pheromone-binding protein2 (OfurPBP2), present in the male moth antenna, plays a role in the detection of female-secreted pheromone in a process that leads to mating. To understand the structural mechanism of pheromone binding and release in this pest, we have initiated characterization of OfurPBP2 by solution NMR. Here, we report the backbone resonance assignments and the secondary structural elements of OfurPBP2 at pH 6.5 using uniformly 13C, 15N-labeled protein with various triple resonance NMR experiments. The assignments are 97 % completed for backbone and 88 % completed for side-chain resonances. The secondary structure of OfurPBP2, based on backbone chemical shifts, consists of eight α-helices, including a well-structured C-terminal helix.
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Structural and Functional Characterization of European Corn Borer, Ostrinia nubilalis, Pheromone Binding Protein 3
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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- PAR ID:
- 10345462
- Date Published:
- Journal Name:
- Journal of agricultural and food chemistry
- Volume:
- 69
- Issue:
- 46
- ISSN:
- 1520-5118
- Page Range / eLocation ID:
- 14013-14023
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Lepidopteran male moths have an extraordinarily sensitive olfactory system that is capable of detecting and responding to minute amounts of female-secreted pheromones over great distances. Pheromone-binding proteins (PBPs) in male antennae ferry the hydrophobic ligand across the aqueous lymph to the olfactory receptor neuron triggering the response. PBPs bind ligands at physiological pH of the lymph and release them at acidic pH near the receptor while undergoing a conformational change. InAnthereae polyphemusPBP1, ligand binding to the hydrophobic pocket and its release is regulated by two biological gates: His70 and His95 at one end of the pocket and C-terminus tail at the other end. Interestingly, in Asian corn borerOstrinia furnacalisPBP2 (OfurPBP2), critical residues for ligand binding and release are substituted in both biological gates. The impact of these substitutions on the ligand binding and release mechanism in OfurPBP2 is not known. We report here overexpression of soluble OfurPBP2 and structural characterization at high and low pH by circular dichroism (CD) and NMR. Ligand binding and ab initio model development were carried out with fluorescence and small-angle X-ray scattering (SAXS) respectively. OfurPBP2 in solution at pH 6.5 is homogeneous, well-folded and has a compact globular shape.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1021/acs.jafc.1c03775
