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Olfactory proteins mediating chemical communication in the navel orangeworm moth, Amyelois transitella.

Leal WS, Ishida Y, Pelletier J, Xu W, Rayo J, Xu X, Ames JB - PLoS ONE (2009)

Bottom Line: We have cloned nine cDNAs encoding olfactory proteins from the navel orangeworm, including two pheromone-binding proteins, two general odorant-binding proteins, one chemosensory protein, one glutathione S-transferase, one antennal binding protein X, one sensory neuron membrane protein, and one odorant receptor.Of these, AtraPBP1 is highly enriched in male antennae.Fluorescence, CD and NMR studies suggest a dramatic pH-dependent conformational change, with high affinity to pheromone constituents at neutral pH and no binding at low pH.

View Article: PubMed Central - PubMed

Affiliation: Department of Entomology, University of California Davis, Davis, California, United States of America. wsleal@ucdavis.edu

ABSTRACT

Background: The navel orangeworm, Amyelois transitella Walker (Lepidoptera: Pyralidae), is the most serious insect pest of almonds and pistachios in California for which environmentally friendly alternative methods of control--like pheromone-based approaches--are highly desirable. Some constituents of the sex pheromone are unstable and could be replaced with parapheromones, which may be designed on the basis of molecular interaction of pheromones and pheromone-detecting olfactory proteins.

Methodology: By analyzing extracts from olfactory and non-olfactory tissues, we identified putative olfactory proteins, obtained their N-terminal amino acid sequences by Edman degradation, and used degenerate primers to clone the corresponding cDNAs by SMART RACE. Additionally, we used degenerate primers based on conserved sequences of known proteins to fish out other candidate olfactory genes. We expressed the gene encoding a newly identified pheromone-binding protein, which was analyzed by circular dichroism, fluorescence, and nuclear magnetic resonance, and used in a binding assay to assess affinity to pheromone components.

Conclusion: We have cloned nine cDNAs encoding olfactory proteins from the navel orangeworm, including two pheromone-binding proteins, two general odorant-binding proteins, one chemosensory protein, one glutathione S-transferase, one antennal binding protein X, one sensory neuron membrane protein, and one odorant receptor. Of these, AtraPBP1 is highly enriched in male antennae. Fluorescence, CD and NMR studies suggest a dramatic pH-dependent conformational change, with high affinity to pheromone constituents at neutral pH and no binding at low pH.

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Binding of a pheromone analog to AtraPBP1.Competitive binding of a pheromone analog, Z11C16COCF3, and the best natural ligand, Z11Z13-16OAc. Both ligands at equimolar concentration were incubated with AtraPBP1 at the same time. AtraPBP1 bound with much higher affinity to the pheromone analog and even retained the ligand at low pH.
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pone-0007235-g013: Binding of a pheromone analog to AtraPBP1.Competitive binding of a pheromone analog, Z11C16COCF3, and the best natural ligand, Z11Z13-16OAc. Both ligands at equimolar concentration were incubated with AtraPBP1 at the same time. AtraPBP1 bound with much higher affinity to the pheromone analog and even retained the ligand at low pH.

Mentions: To further explore the potential use of AtraPBP1 for the development of parapheromones, we tested binding of a pheromone analog, (Z)-1,1,1-trifluoro-13-octadecen-2-one (hereafter referred to as Z11C16COCF3). Trifluoromethyl ketones (TFMK) [44] are compounds which inhibit a variety of hydrolytic enzymes, such as acetylcholinesterase, chymotrypsin, trypsin, juvenile hormone esterase, human liver microsomal CEs, and pheromone degrading esterases in male olfactory tissues. They have been demonstrated to interrupt insect chemical communication [45], [46] and to bind to pheromone-binding proteins [47], but their mode of action is still a matter of debate. We compared by competitive binding the affinity of Z11C16COCF3 and Z11Z13-16OAc to AtraPBP1. Surprisingly, Z11C16COCF3 binds to AtraPBP1 with much higher affinity than the behavioural antagonist Z11Z13-16OAc (Fig. 13). Although binding activity decreased dramatically at low pH, this TFMK showed binding affinity at low pH almost half of that of the best natural ligand (Z11Z13-16OAc) at neutral pH (Fig. 13). We, therefore, concluded that AtraPBP1 may be employed for the development of a affinity-based approach for the development of parapheromones.


Olfactory proteins mediating chemical communication in the navel orangeworm moth, Amyelois transitella.

Leal WS, Ishida Y, Pelletier J, Xu W, Rayo J, Xu X, Ames JB - PLoS ONE (2009)

Binding of a pheromone analog to AtraPBP1.Competitive binding of a pheromone analog, Z11C16COCF3, and the best natural ligand, Z11Z13-16OAc. Both ligands at equimolar concentration were incubated with AtraPBP1 at the same time. AtraPBP1 bound with much higher affinity to the pheromone analog and even retained the ligand at low pH.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2749207&req=5

pone-0007235-g013: Binding of a pheromone analog to AtraPBP1.Competitive binding of a pheromone analog, Z11C16COCF3, and the best natural ligand, Z11Z13-16OAc. Both ligands at equimolar concentration were incubated with AtraPBP1 at the same time. AtraPBP1 bound with much higher affinity to the pheromone analog and even retained the ligand at low pH.
Mentions: To further explore the potential use of AtraPBP1 for the development of parapheromones, we tested binding of a pheromone analog, (Z)-1,1,1-trifluoro-13-octadecen-2-one (hereafter referred to as Z11C16COCF3). Trifluoromethyl ketones (TFMK) [44] are compounds which inhibit a variety of hydrolytic enzymes, such as acetylcholinesterase, chymotrypsin, trypsin, juvenile hormone esterase, human liver microsomal CEs, and pheromone degrading esterases in male olfactory tissues. They have been demonstrated to interrupt insect chemical communication [45], [46] and to bind to pheromone-binding proteins [47], but their mode of action is still a matter of debate. We compared by competitive binding the affinity of Z11C16COCF3 and Z11Z13-16OAc to AtraPBP1. Surprisingly, Z11C16COCF3 binds to AtraPBP1 with much higher affinity than the behavioural antagonist Z11Z13-16OAc (Fig. 13). Although binding activity decreased dramatically at low pH, this TFMK showed binding affinity at low pH almost half of that of the best natural ligand (Z11Z13-16OAc) at neutral pH (Fig. 13). We, therefore, concluded that AtraPBP1 may be employed for the development of a affinity-based approach for the development of parapheromones.

Bottom Line: We have cloned nine cDNAs encoding olfactory proteins from the navel orangeworm, including two pheromone-binding proteins, two general odorant-binding proteins, one chemosensory protein, one glutathione S-transferase, one antennal binding protein X, one sensory neuron membrane protein, and one odorant receptor.Of these, AtraPBP1 is highly enriched in male antennae.Fluorescence, CD and NMR studies suggest a dramatic pH-dependent conformational change, with high affinity to pheromone constituents at neutral pH and no binding at low pH.

View Article: PubMed Central - PubMed

Affiliation: Department of Entomology, University of California Davis, Davis, California, United States of America. wsleal@ucdavis.edu

ABSTRACT

Background: The navel orangeworm, Amyelois transitella Walker (Lepidoptera: Pyralidae), is the most serious insect pest of almonds and pistachios in California for which environmentally friendly alternative methods of control--like pheromone-based approaches--are highly desirable. Some constituents of the sex pheromone are unstable and could be replaced with parapheromones, which may be designed on the basis of molecular interaction of pheromones and pheromone-detecting olfactory proteins.

Methodology: By analyzing extracts from olfactory and non-olfactory tissues, we identified putative olfactory proteins, obtained their N-terminal amino acid sequences by Edman degradation, and used degenerate primers to clone the corresponding cDNAs by SMART RACE. Additionally, we used degenerate primers based on conserved sequences of known proteins to fish out other candidate olfactory genes. We expressed the gene encoding a newly identified pheromone-binding protein, which was analyzed by circular dichroism, fluorescence, and nuclear magnetic resonance, and used in a binding assay to assess affinity to pheromone components.

Conclusion: We have cloned nine cDNAs encoding olfactory proteins from the navel orangeworm, including two pheromone-binding proteins, two general odorant-binding proteins, one chemosensory protein, one glutathione S-transferase, one antennal binding protein X, one sensory neuron membrane protein, and one odorant receptor. Of these, AtraPBP1 is highly enriched in male antennae. Fluorescence, CD and NMR studies suggest a dramatic pH-dependent conformational change, with high affinity to pheromone constituents at neutral pH and no binding at low pH.

Show MeSH
Related in: MedlinePlus