研究人员表示，大多数昆虫，包括以人类为目标的蚊子，都通过气味激活的离子通道复合物检测气味，该复合物由一个不同的气味剂结合亚基（OR）和一个保守的共受体亚基（Orco）组成。
作为了解气味如何激活这些异源受体的基础，研究人员报告了两种不同的异源气味受体复合物的冷冻电镜（cryo-EM）结构，这些复合物含有来自疾病媒介蚊子埃及伊蚊或冈比亚按蚊的OR。
这些结构揭示了1个OR与3个Orco亚基之间意想不到的配比关系。气味剂结合和未结合状态下的结构比较表明，气味剂与唯一的OR亚基结合就足以打开通道孔，这揭示了OR的激活机制和理解昆虫气味受体敏感性演化的概念框架。
附：英文原文
Title: Structural basis of odor sensing by insect heteromeric odorant receptors
Author: Jiawei Zhao, Andy Q. Chen, Jaewook Ryu, Josefina del Mármol
Issue&Volume: 2024-06-13
Abstract: Most insects, including human-targeting mosquitoes, detect odors through odorant-activated ion channel complexes consisting of a divergent odorant-binding subunit (OR) and a conserved co-receptor subunit (Orco). As a basis for understanding how odorants activate these heteromeric receptors, we report here cryo–electron microscopy (cryo-EM) structures of two different heteromeric odorant receptor complexes containing ORs from disease-vector mosquitos Aedes aegypti or Anopheles gambiae. These structures reveal an unexpected stoichiometry of 1 OR to 3 Orco subunits. Comparison of structures in odorant-bound and unbound states indicates that odorant binding to the sole OR subunit is sufficient to open the channel pore, suggesting a mechanism of OR activation and a conceptual framework for understanding evolution of insect odorant receptor sensitivity.
DOI: adn6384
Source: https://www.science.org/doi/10.1126/science.adn6384