Cloning of two odorant binding protein genes in Conopomorpha sinensis Bradley and their molecular docking with sex pheromone components

【Objective】 This study clarified the function of odorant binding proteins （OBPs） of Conopomorpha sinensis Bradley in the recognition of sex pheromones， which could provide theoretical basis for elucidating the chemical communication mechanism underlying sex pheromone recognition in Conopomorpha sinensis Bradley.【Method】 Based on transcriptome data from the antennae of female and male Conopomorpha sinensis Bradley，the CsOBPs proteins related to the recognition of sex pheromones were obtained， rapid amplification of cDNA end （RACE） technique was adopted to clone the full-length of CsOBPs gene and bioinformatics analysis was also conducted. The expression patterns of CsOBPs gene in different tissues （antennae， head， thorax， abdomen， leg， wing） and time points （00：00，04：00，08：00，12：00，16：00，20：00，24：00） of the 3-day-old adult of Conopomorpha sinensis Bradley were detected by real-time fluorescence quantitative PCR. The tertiary structure model of the CsOBPs protein was constructed using AlphaFold 2， and its binding ability with sex pheromones was analyzed through molecular docking.【Result】 Two sex pheromone recognition-related OBPs genes sequences，CsOBP1 and CsOBP2，were successfully cloned. The full-length gene sequences were obtained through amplification. CsOBP1 gene was 859 bp in length，encoding 121 amino acids residues with a molecular weight of 14.27 kD and theoretical isoelectric point of 5.91. CsOBP2 gene was 824 bp in length，encoding 160 amino acids residues with a molecular weight of 18.24 kD and theoretical isoelectric point of 5.27. Real-time fluorescence quantitative PCR analysis revealed that， both genes were expressed in various tissues of Conopomorpha sinensis Bradley， with the highest expression level in male antennae. Additionally，the expression of the two genes peaked at night，which was consistent with the mating behavior rhythm of this pest. The results of homology modeling showed that CsOBP1 and CsOBP2 proteins possessed the typical characteristics of OBPs，containing three pairs of disulfide bonds formed by six conserved cysteine residues. The results of molecular docking indicated that CsOBP1 and CsOBP2 proteins had strong binding ability for six sex pheromone components with binding energies ranging from -5.3 to -9.1 kcal/mol. Molecular dynamics trajectory simulation results indicated that CsOBP1 and CsOBP2 proteins formed stable complexes with sex pheromone components primarily through van der Waals interaction energy and nonpolar solvation energy.【Conclusion】 CsOBP1 and CsOBP2 genes are associated with sex pheromone recognition， and CsOBP1 and CsOBP2 can act as sex pheromone binding proteins involved in regulating the process of sex pheromone recognition in Conopomorpha sinensis Bradley.