Structural titration of receptor ion channel GLIC gating by HS-AFM
Image Processing, Computer-Assisted
Microscopy, Atomic Force
© 2018 National Academy of Sciences.All Rights Reserved. Gloeobacter violaceus ligand-gated ion channel (GLIC), a protongated, 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 performstructural 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.
PubMed Central ID
Digital Object Identifier (DOI)
Additional Document Info
has global citation frequency