Biochemistry and Structural Biology, Cell and Developmental Biology, and Molecular Biology Program, Weill Cornell Graduate School of Biomedical Sciences, New York, NY, USA.
Weill Cornell Medicine, Department of Anesthesiology, New York, NY, USA.
Nat Struct Mol Biol. 2024 Aug;31(8):1286-1295. doi: 10.1038/s41594-024-01260-3. Epub 2024 Apr 17.
The Pyrococcus horikoshii amino acid transporter Glt revealed, like other channels and transporters, activity mode switching, previously termed wanderlust kinetics. Unfortunately, to date, the basis of these activity fluctuations is not understood, probably due to a lack of experimental tools that directly access the structural features of transporters related to their instantaneous activity. Here, we take advantage of high-speed atomic force microscopy, unique in providing simultaneous structural and temporal resolution, to uncover the basis of kinetic mode switching in proteins. We developed membrane extension membrane protein reconstitution that allows the analysis of isolated molecules. Together with localization atomic force microscopy, principal component analysis and hidden Markov modeling, we could associate structural states to a functional timeline, allowing six structures to be solved from a single molecule, and an inward-facing state, IFS, to be determined as a kinetic dead-end in the conformational landscape. The approaches presented on Glt are generally applicable and open possibilities for time-resolved dynamic single-molecule structural biology.
日本热球菌氨基酸转运蛋白 Glt 的揭示,与其他通道和转运蛋白一样,具有活动模式转换的特性,以前称为漫游癖动力学。不幸的是,迄今为止,这些活性波动的基础尚不清楚,这可能是由于缺乏直接访问与瞬时活性相关的转运蛋白结构特征的实验工具。在这里,我们利用高速原子力显微镜的独特优势,提供同时的结构和时间分辨率,来揭示蛋白质中动力学模式转换的基础。我们开发了膜延伸膜蛋白重构,允许对分离的分子进行分析。与定位原子力显微镜、主成分分析和隐马尔可夫模型一起,我们可以将结构状态与功能时间线相关联,允许从单个分子中解决六个结构,并确定内向状态 IFS 作为构象景观中的动力学终点。所提出的方法在 Glt 上具有普遍适用性,并为时间分辨的动态单分子结构生物学开辟了可能性。