State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
J Chem Ecol. 2011 Feb;37(2):189-94. doi: 10.1007/s10886-010-9902-3. Epub 2010 Dec 24.
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.
昆虫的化学感受是由小分子气味结合蛋白（OBPs）介导的，这些蛋白被认为通过水相亲和淋巴将亲脂性刺激物传递到嗅觉受体细胞。结合实验和最近对 OBPs 的结构研究表明，它们具有多功能性，能够容纳不同形状和化学结构的配体。我们在原核表达系统中表达并纯化了来自寄生蜂（膜翅目：Braconidae）的 7 种重组 MmedOBPs（MmedOBP1-MmedOBP7）。使用 4,4'-二苯胺-1,1'-联萘-5,5'-磺酸（bis-ANS）作为荧光探针，在体外研究了这 7 种 MmedOBPs 与 50 种小分子有机化合物的配体结合特异性。结果表明，所有 M. mediator OBPs 都可以与不同结合亲和力的各种气味分子结合。对于所有 7 种 MmedOBPs 来说，β-紫罗兰酮是最好的配体。MmedOBP2 对一些芳香族化合物具有亲和力，而 MmedOBP4 和 MmedOBP6 结合了几种萜类化合物。MmedOBP5 结合了β-紫罗兰酮，但不结合我们测试的任何其他潜在配体。
