@article{TEXTUAL, recid = {9888}, author = {Basak, Sandip and Schmandt, Nicolaus and Gicheru, Yvonne and Chakrapani, Sudha}, title = {Crystal structure and dynamics of a lipid-induced potential desensitized-state of a pentameric ligand-gated channel}, journal = {eLife}, address = {2017-03-06}, number = {TEXTUAL}, abstract = {Desensitization in pentameric ligandgated ion channels plays an important role in regulating neuronal excitability. Here, we show that docosahexaenoic acid (DHA), a key ω−3 polyunsaturated fatty acid in synaptic membranes, enhances the agonist-induced transition to the desensitized state in the prokaryotic channel GLIC. We determined a 3.25 Å crystal structure of the GLIC-DHA complex in a potentially desensitized conformation. The DHA molecule is bound at the channel-periphery near the M4 helix and exerts a long-range allosteric effect on the pore across domain-interfaces. In this previously unobserved conformation, the extracellular-half of the porelining M2 is splayed open, reminiscent of the open conformation, while the intracellular-half is constricted, leading to a loss of both water and permeant ions. These findings, in combination with spin-labeling/EPR spectroscopic measurements in reconstituted-membranes, provide novel mechanistic details of desensitization in pentameric channels.}, url = {http://knowledge.uchicago.edu/record/9888}, }