{"title":"Ligand binding properties of three odorant-binding proteins in striped flea beetle Phyllotreta striolata towards two phthalate esters","authors":"Yong Xiao, Yuhong Wu, Chunmei Lei, Fei Yin, Zhengke Peng, Xiangfeng Jing, Yongjun Zhang, Zhenyu Li","doi":"10.1111/imb.12907","DOIUrl":null,"url":null,"abstract":"<p>Odorant-binding proteins (OBPs) initiate insect olfactory perception and mediate specific binding and selection of odorants via uncertain binding mechanisms. We characterized the binding characteristics of four OBPs from the striped flea beetle <i>Phyllotreta striolata</i> (SFB), a major cruciferous crop pest. Tissue expression analysis revealed that the two ABPII OBPs (PstrOBP12 and PstrOBP19) were highly expressed mainly in the antenna, whereas the two minus-C OBPs (PstrOBP13 and PstrOBP16) showed a broad expression pattern. Competitive binding assays of cruciferous plant volatiles showed that PstrOBP12, PstrOBP16 and PstrOBP19 had very strong binding capacities for only two phthalate esters (<i>K</i><sub>i</sub> < 20 μM), and PstrOBP13 specifically bound to four aromatic volatiles (<i>K</i><sub>i</sub> < 11 μM). Fluorescence quenching assays displayed that two phthalate esters bound to three PstrOBPs via different quenching mechanisms. PstrOBP12/PstrOBP16–diisobutyl phthalate and PstrOBP19–bis(6-methylheptyl) phthalate followed static quenching, while PstrOBP12/PstrOBP16–bis(6-methylheptyl) phthalate and PstrOBP19–diisobutyl phthalate followed dynamic quenching. Homology modelling and molecular docking displayed that PstrOBP12–diisobutyl phthalate was driven by H-bonding and van der Waals interactions, while PstrOBP16–diisobutyl phthalate and PstrOBP19–bis(6-methylheptyl) phthalate followed hydrophobic interactions. Finally, behavioural activity analysis demonstrated that phthalate esters exhibited different behavioural activities of SFB at different doses, with low doses attracting and high doses repelling. Overall, we thus revealed the different binding properties of the three PstrOBPs to two phthalate esters, which was beneficial in shedding light on the ligand-binding mechanisms of OBPs.</p>","PeriodicalId":13526,"journal":{"name":"Insect Molecular Biology","volume":null,"pages":null},"PeriodicalIF":2.3000,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Insect Molecular Biology","FirstCategoryId":"97","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1111/imb.12907","RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Odorant-binding proteins (OBPs) initiate insect olfactory perception and mediate specific binding and selection of odorants via uncertain binding mechanisms. We characterized the binding characteristics of four OBPs from the striped flea beetle Phyllotreta striolata (SFB), a major cruciferous crop pest. Tissue expression analysis revealed that the two ABPII OBPs (PstrOBP12 and PstrOBP19) were highly expressed mainly in the antenna, whereas the two minus-C OBPs (PstrOBP13 and PstrOBP16) showed a broad expression pattern. Competitive binding assays of cruciferous plant volatiles showed that PstrOBP12, PstrOBP16 and PstrOBP19 had very strong binding capacities for only two phthalate esters (Ki < 20 μM), and PstrOBP13 specifically bound to four aromatic volatiles (Ki < 11 μM). Fluorescence quenching assays displayed that two phthalate esters bound to three PstrOBPs via different quenching mechanisms. PstrOBP12/PstrOBP16–diisobutyl phthalate and PstrOBP19–bis(6-methylheptyl) phthalate followed static quenching, while PstrOBP12/PstrOBP16–bis(6-methylheptyl) phthalate and PstrOBP19–diisobutyl phthalate followed dynamic quenching. Homology modelling and molecular docking displayed that PstrOBP12–diisobutyl phthalate was driven by H-bonding and van der Waals interactions, while PstrOBP16–diisobutyl phthalate and PstrOBP19–bis(6-methylheptyl) phthalate followed hydrophobic interactions. Finally, behavioural activity analysis demonstrated that phthalate esters exhibited different behavioural activities of SFB at different doses, with low doses attracting and high doses repelling. Overall, we thus revealed the different binding properties of the three PstrOBPs to two phthalate esters, which was beneficial in shedding light on the ligand-binding mechanisms of OBPs.
期刊介绍:
Insect Molecular Biology has been dedicated to providing researchers with the opportunity to publish high quality original research on topics broadly related to insect molecular biology since 1992. IMB is particularly interested in publishing research in insect genomics/genes and proteomics/proteins.
This includes research related to:
• insect gene structure
• control of gene expression
• localisation and function/activity of proteins
• interactions of proteins and ligands/substrates
• effect of mutations on gene/protein function
• evolution of insect genes/genomes, especially where principles relevant to insects in general are established
• molecular population genetics where data are used to identify genes (or regions of genomes) involved in specific adaptations
• gene mapping using molecular tools
• molecular interactions of insects with microorganisms including Wolbachia, symbionts and viruses or other pathogens transmitted by insects
Papers can include large data sets e.g.from micro-array or proteomic experiments or analyses of genome sequences done in silico (subject to the data being placed in the context of hypothesis testing).