A Determinant of Odorant Specificity Is Located at the Extracellular Loop 2-Transmembrane Domain 4 Interface of an Anopheles gambiae Odorant Receptor Subunit
A Determinant of Odorant Specificity Is Located at the Extracellular Loop 2-Transmembrane Domain 4 Interface of an Anopheles gambiae Odorant Receptor Subunit
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DOI：
10.1093/chemse/bju048
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发表时间：
2014-11-01
期刊：
影响因子：
3.5
通讯作者：
Luetje, Charles W.
中科院分区：
文献类型：
--
作者：
Hughes, David T.;Wang, Guirong;Luetje, Charles W.
为了探究冈比亚疟蚊气味受体特异性的结构基础，利用2电极电压箝法测定了非洲爪蚊卵母细胞中与Agam\Orco（辅助受体亚基）联合表达的气味结合亚基（Agam\ Orco）对25种结构相关气味的影响。Agam\Or13和Agam\Or15显示82%的氨基酸同源性，具有相似的气味响应谱，但有些不同。在Agam\Or15和Agam\Or13之间交换37个不同残基的突变分析中，使用了苯乙酮与4-甲基苯酚响应的比率。11个突变引起了气味反应的显著变化。丙氨酸195突变导致Agam\Or15向Agam\Or13的响应率发生最大的变化。对残基195的一系列突变进行浓度-响应分析，发现其对苯乙酮的敏感性有较大影响，EC50值变化范围为100 ~ 1800倍，且与残基侧链长度相关。对丙烯酮和苯甲醛也得到了类似的结果。但是，对于其他气味剂，如4-甲基苯酚，4-甲基苯甲醛和4-甲基丙烯酮，突变的影响要小得多(EC50值变化为
To explore the structural basis for odorant specificity in odorant receptors of the human malaria vector mosquito, Anopheles gambiae, odorant-binding subunits (Agam\Ors) expressed in Xenopus oocytes in combination with Agam\Orco (coreceptor subunit) were assayed by 2-electrode voltage clamp against 25 structurally related odorants. Agam\Or13 and Agam\Or15 display 82% amino acid identity and had similar, but somewhat distinct odorant response profiles. The ratio of acetophenone to 4-methylphenol responses was used in a mutation-based analysis of Agam\Or15, interchanging 37 disparate residues between Agam\Or15 and Agam\Or13. Eleven mutations caused significant changes in odorant responsiveness. Mutation of alanine 195 resulted in the largest shift in response ratio from Agam\Or15 toward Agam\Or13. Concentration-response analysis for a series of mutations of residue 195 revealed a large effect on acetophenone sensitivity, with EC50 values varying by >1800-fold and correlating with residue side chain length. Similar results were obtained for propiophenone and benzaldehyde. But, for other odorants, such as 4-methylphenol, 4-methylbenzaldehyde, and 4-methylpropiophenone, the effect of mutation was much smaller (EC50 values varied by