Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario, Canada.
Biophys J. 2011 Aug 3;101(3):L23-5. doi: 10.1016/j.bpj.2011.06.035.
Solid-state NMR spectroscopy is an efficient tool for following conformational dynamics of membrane proteins at atomic resolution. We used this technique for the site-specific detection of light-induced hydrogen-deuterium exchange in the lipid-embedded heptahelical transmembrane photosensor Anabaena sensory rhodopsin to pinpoint the location of its conformational changes upon activation. We show that the light-induced conformational changes result in a dramatic, but localized, increase in the exchange in the transmembrane regions. Most notably, the cytoplasmic half of helix G and the cytoplasmic ends of helices B and C exchange more extensively, probably as a result of their relative displacement in the activated state, allowing water to penetrate into the core of the protein. These light-induced rearrangements must provide the structural basis for the photosensory function of Anabaena sensory rhodopsin.
固态核磁共振波谱是一种有效的工具,可用于在原子分辨率下跟踪膜蛋白的构象动力学。我们使用该技术对脂质嵌入的七螺旋跨膜光传感器鱼腥蓝细菌感受态视紫红质中的光诱导氢氘交换进行了定点检测,以确定其在激活时构象变化的位置。我们表明,光诱导的构象变化导致跨膜区域的交换显著增加,但局部增加。值得注意的是,螺旋 G 的胞质半部分和螺旋 B 和 C 的胞质末端交换更为广泛,可能是由于它们在激活状态下的相对位移,允许水渗透到蛋白质的核心。这些光诱导的重排必须为鱼腥蓝细菌感受态视紫红质的光感觉功能提供结构基础。