title: Binding characterization of recombinant odorant-binding proteins from the parasitic wasp, Microplitis mediator (Hymenoptera: Braconidae).
abstract: Chemoreception in insects is mediated by small odorant-binding proteins (OBPs) that are believed to carry lipophilic stimuli to the olfactory receptor cells through the aqueous sensillar lymph. Binding experiments and recent structural studies of OBPs have illustrated their versatility and ability to accommodate ligands of different shapes and chemical structures. We expressed and purified seven recombinant OBPs (MmedOBP1-MmedOBP7) from the parasitic wasp, Microplitis mediator (Hymenoptera: Braconidae) in a prokaryotic expression system. With 4,4'-dianilino-1,1'-binaphthyl-5,5'-sulfonic acid (bis-ANS) as a fluorescent probe, the ligand-binding specificities of these seven MmedOBPs with 50 small organic compounds were investigated in vitro. The results revealed that all of the M. mediator OBPs can bind a wide variety of odorant molecules with different binding affinities. The best ligand for all seven MmedOBPs was β-ionone. MmedOBP2 showed affinity for some aromatic compounds, whereas MmedOBP4 and MmedOBP6 bound several terpenoids. MmedOBP5 bound β-ionone, but did not bind any of the other potential ligands that we tested.
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhang
authors.forename: Li-Zhen
authors.initials: LZ
authors.lastname: Chen
authors.forename: Shao-Hua
authors.initials: SH
authors.lastname: Gu
authors.forename: Jin-Jie
authors.initials: JJ
authors.lastname: Cui
authors.forename: Xi-Wu
authors.initials: XW
authors.lastname: Gao
authors.forename: Yong-Jun
authors.initials: YJ
authors.lastname: Zhang
authors.forename: Yu-Yuan
authors.initials: YY
authors.lastname: Guo
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D005260:Female; D005456:Fluorescent Dyes / Q000737:chemistry / Q000378:metabolism; D006927:Hymenoptera; D019476:Insect Proteins / Q000378:metabolism*; D008297:Male; D010944:Plants / Q000737:chemistry; D011485:Protein Binding; D018035:Receptors, Odorant / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism*; D013379:Substrate Specificity; D055549:Volatile Organic Compounds / Q000378:metabolism
chemical_list: D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D019476:Insect Proteins; D018035:Receptors, Odorant; D011994:Recombinant Proteins; D055549:Volatile Organic Compounds; C045648:odorant-binding protein