Structural titration of receptor ion channel GLIC gating by HS-AFM.

TitleStructural titration of receptor ion channel GLIC gating by HS-AFM.
Publication TypeJournal Article
Year of Publication2018
AuthorsRuan Y, Kao K, Lefebvre S, Marchesi A, Corringer P-J, Hite RK, Scheuring S
JournalProc Natl Acad Sci U S A
Date Published2018 Sep 04

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.

Alternate JournalProc. Natl. Acad. Sci. U.S.A.
PubMed ID30181288