Ligand-gated pentameric ion channels, from binding to gating.

Area of Science:

• Structural biology
• Neuroscience
• Biochemistry

Background:

• Ligand-gated ion channels are crucial for neurotransmission.
• Understanding their gating mechanisms is key to drug development.
• Previous models lacked detailed structural insights into conserved gating.

Purpose of the Study:

• To model the ligand binding and activation mechanism of ligand-gated pentameric ion channels.
• To compare common and distinct features across various pentameric receptors.
• To elucidate the structural basis of channel gating.

Main Methods:

• X-ray crystallography of molluscan acetylcholine-binding proteins.
• X-ray crystallography of prokaryotic proton-activated ion channels (ELIC and GLIC).
• Comparative structural analysis of ligand interactions.

Main Results:

• Detailed structural models of ligand binding and activation were generated.
• Commonalities and differences in agonist, antagonist, and allosteric modulator binding were identified at subunit interfaces.
• Conformational waves propagating from ligand binding sites to pore domains were elucidated.

Conclusions:

• Ligand interactions at subunit interfaces initiate conformational changes essential for channel gating.
• The elucidated mechanism provides a unified view of pentameric ion channel function.
• This work offers a foundation for designing novel therapeutics targeting these channels.