Structural titration of receptor ion channel GLIC gating by HS-AFM.
| Publication Type | Academic Article |
| Authors | Ruan Y, Kao K, Lefebvre S, Marchesi A, Corringer P, Hite R, Scheuring S |
| Journal | Proc Natl Acad Sci U S A |
| Volume | 115 |
| Issue | 41 |
| Pagination | 10333-10338 |
| Date Published | 09/04/2018 |
| ISSN | 1091-6490 |
| Keywords | Bacterial Proteins, Cysteine Loop Ligand-Gated Ion Channel Receptors, Microscopy, Atomic Force |
| Abstract | Gloeobacter violaceus ligand-gated ion channel (GLIC), a proton-gated, cation-selective channel, is a prokaryotic homolog of the pentameric Cys-loop receptor ligand-gated ion channel family. Despite large changes in ion conductance, small conformational changes were detected in X-ray structures of detergent-solubilized GLIC at pH 4 (active/desensitized state) and pH 7 (closed state). Here, we used high-speed atomic force microscopy (HS-AFM) combined with a buffer exchange system to perform structural titration experiments to visualize GLIC gating at the single-molecule level under native conditions. Reference-free 2D classification revealed channels in multiple conformational states during pH gating. We find changes of protein-protein interactions so far elusive and conformational dynamics much larger than previously assumed. Asymmetric pentamers populate early stages of activation, which provides evidence for an intermediate preactivated state. |
| DOI | 10.1073/pnas.1805621115 |
| PubMed ID | 30181288 |
| PubMed Central ID | PMC6187180 |