Molecule of the Month: Glutamate-gated Chloride Receptors
The antibiotic ivermectin attacks glutamate-gated chloride channels, paralyzing parasitic worms.
Exploring the Structure
Glutamate-gated Chloride Channel (PDB entries 4tnv and 3rif)
Researchers have captured these channels in many states, revealing how they open and close in response to binding of their ligands. On the right is a closed channel (PDB entry 4tnv ). A leucine amino acid forms a tight ring at the center of the channel that blocks passage of ions. On the left is a channel with glutamate and ivermectin bound, which has opened the channel, allowing ions to pass (PDB entry 3rif ). To explore these structures in more detail, click on the image for an interactive JSmol.
Topics for Further Discussion
- Structures for many similar channels are available in the PDB. Try searching for "Cys-loop receptor" to see a few examples.
- When you look at the PDB entries for glutamate-gated chloride channels, you'll find that they include five antibodies bound to the ligand-binding portion of the molecule. Why are these included in the structure?
Related PDB-101 Resources
- Browse Cellular Signaling
- Browse Drug Action
- 3jad: J. Du, W. Lu, S. Wu, Y. Cheng & E. Gouaux (2015) Glycine receptor mechanism elucidated by electron cryo-microscopy. Nature 526, 224-229.
- 4tnv: T. Althoff, R. E. Hibbs, S. Banerjee & E. Gouaux (2014) X-ray structures of GluCl in apo states reveal a gating mechanism of Cys-loop receptors. Nature 512, 333-337.
- 4hfe: L. Sauguet, R. J. Howard, L. Malherbe, U. S. Lee, P. J. Corringer, R. A. Harris & M. Delarue (2013) Structural basis for potentiation by alcohols and anaesthetics in a ligand-gated ion channel. Nature Communications 4, 1697.
- A. J. Wolstenholme (2012) Glutamate-gated chloride channels. Journal of Biological Chemistry 287, 40232-40238.
- 3rif: R. E. Hibbs & E. Gouaux (2011) Principles of activation and permeation in an anion-selective Cys-loop receptor. Nature 474, 54-60.
- L. M. Fox (2006) Ivermectin: uses and impact 20 years on. Current Opinion in Infectious Diseases 19, 588-593.
November 2015, David Goodselldoi:10.2210/rcsb_pdb/mom_2015_11