McGillivray Duncan J, Valincius Gintaras, Heinrich Frank, Robertson Joseph W F, Vanderah David J, Febo-Ayala Wilma, Ignatjev Ilja, Lösche Mathias, Kasianowicz John J
National Institute of Standards and Technology (NIST) Center for Neutron Research, Gaithersburg, Maryland, USA.
Biophys J. 2009 Feb 18;96(4):1547-53. doi: 10.1016/j.bpj.2008.11.020.
We demonstrate a method for simultaneous structure and function determination of integral membrane proteins. Electrical impedance spectroscopy shows that Staphylococcus aureus alpha-hemolysin channels in membranes tethered to gold have the same properties as those formed in free-standing bilayer lipid membranes. Neutron reflectometry provides high-resolution structural information on the interaction between the channel and the disordered membrane, validating predictions based on the channel's x-ray crystal structure. The robust nature of the membrane enabled the precise localization of the protein within 1.1 A. The channel's extramembranous cap domain affects the lipid headgroup region and the alkyl chains in the outer membrane leaflet and significantly dehydrates the headgroups. The results suggest that this technique could be used to elucidate molecular details of the association of other proteins with membranes and may provide structural information on domain organization and stimuli-responsive reorganization for transmembrane proteins in membrane mimics.
我们展示了一种用于同时测定整合膜蛋白结构与功能的方法。电阻抗谱表明，固定在金表面的膜中金黄色葡萄球菌α-溶血素通道与在独立双层脂质膜中形成的通道具有相同特性。中子反射测量法提供了关于通道与无序膜之间相互作用的高分辨率结构信息，验证了基于通道X射线晶体结构的预测。该膜的稳健性质使得能够在1.1埃范围内精确确定蛋白质的位置。通道的膜外帽结构域影响脂质头基团区域和外膜小叶中的烷基链，并使头基团显著脱水。结果表明，该技术可用于阐明其他蛋白质与膜结合的分子细节，并可能为膜模拟物中的跨膜蛋白提供结构域组织和刺激响应性重组的结构信息。
