Athetis lepigone is a polyphagous pest found around
the world that feeds on maize, wheat, and various other important
crops. Although it exhibits a degree of resistance to various chemical
insecticides, an effective pest-control method has not yet been developed.
The sex pheromone communication system plays an essential role in
the mating and reproduction of moths, in which pheromone-binding proteins
(PBPs) are crucial genes. In this study, we cloned and purified the
protein AlepPBP1 using an E. coli expression system
and found it had a higher binding affinity to two sex pheromones of A. lepigone, namely, Z7-12:Ac and Z9-14:Ac (with K
i
0.77 ± 0.10 and 1.10
± 0.20 μM, respectively), than to other plant volatiles.
The binding-mode analysis of protein conformation with equilibrium
stabilization was obtained using molecular dynamics (MD) simulation
and indicated that hydrophobic interactions involving several nonpolar
residues were the main driving force for the binding affinity of AlepPBP1
with sex pheromones. Computational alanine scanning (CAS) was performed
to further identify key amino acid residues and validate their binding
contributions. Each key residue, including Phe36, Trp37, Val52, and
Phe118, was subsequently mutated into alanine using site-directed
mutagenesis. Binding assays showed that the efficient binding abilities
to Z7-12:Ac (F36A, W37A, and F118A) and Z9-14:Ac (F36A, W37A, V52A,
and F118A) were almost lost in the mutated proteins. Our results demonstrated
that these key amino acid residues are crucial for determining the
binding ability of AlepPBP1 to sex pheromones. These findings provide
a basis for the use of AlepPBP1 in the studies as a specific target
for the development of novel behavioral antagonists with marked inhibition
or mating-disruption abilities using computer-aided drug design (CADD).
Hyphantria cunea (Drury) is a destructive
invasive pest species in China that uses type II sex pheromone components.
To date, however, the binding mechanisms of its sex pheromone components
to their respective pheromone-binding proteins (HcunPBPs 1/2/3) have
not been explored. In the current study, all three HcunPBPs were expressed in the antennae of both sexes. The prokaryotic expression
and ligand binding assays were employed to study the binding of the
moth’s four sex pheromone components, including two aldehydes
and two epoxides, and 24 plant volatiles to the HcunPBPs. Our results
showed that the abilities of these HcunPBPs to bind to the aldehydes
were significantly different from binding to the epoxides. These three
HcunPBPs also selectively bind to some of the plant volatiles tested.
Our molecular docking results indicated that some crucial hydrophobic
residues might play a role in the binding of HcunPBPs to their sex
pheromone components. Three HcunPBPs have different selectivities
for pheromone components with both major and minor structural differences.
Our study provides a fundamental insight into the olfactory mechanism
of moths at the molecular level, especially for moth species that
use various type II pheromone components.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.