GABA Binding to an Insect GABA Receptor: A Molecular Dynamics and Mutagenesis Study
Abstract
RDL receptors are GABA-activated inhibitory Cys-loop receptors found throughout the insect CNS. They are a key target for insecticides. Here, we characterize the GABA binding site in RDL receptors using computational and electrophysiological techniques. A homology model of the extracellular domain of RDL was generated and GABA docked into the binding site. Molecular dynamics simulations predicted critical GABA binding interactions with aromatic residues F206, Y254, and Y109 and hydrophilic residues E204, S176, R111, R166, S176, and T251. These residues were mutated, expressed in Xenopus oocytes, and their functions assessed using electrophysiology. The data support the binding mechanism provided by the simulations, which predict that GABA forms many interactions with binding site residues, the most significant of which are cation-π interactions with F206 and Y254, H-bonds with E204, S205, R111, S176, T251, and ionic interactions with R111 and E204. These findings clarify the roles of a range of residues in binding GABA in the RDL receptor, and also show that molecular dynamics simulations are a useful tool to identify specific interactions in Cys-loop receptors.
Additional Information
© 2012 by the Biophysical Society. This is an Open Access article distributed under the terms of the Creative Commons-Attribution Noncommercial License (http://creativecommons.org/licenses/by-nc/2.0/), which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Submitted March 30, 2012, and accepted for publication October 11, 2012. We acknowledge financial support from TheWellcome Trust (WT 81925 to SCRL; SCRL is a Wellcome Trust Senior Research Fellow in Basic Biomedical Science), the European Union 7th Framework Program No. HEALTH-F2-2007-202088 ("NeuroCypres" project) to SCRL; the Medical Research Council (a studentship to I.McG.), the U. S. National Institutes of Health (NS34407 to D.A.D.), and the EPSRC (EP/F037457/1 "Support for the UK Car-Parrinello Consortium") to CM.Attached Files
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Additional details
- PMCID
- PMC3512037
- Eprint ID
- 36161
- Resolver ID
- CaltechAUTHORS:20130104-082120331
- WT 81925
- Wellcome Trust
- HEALTH-F2-2007-202088
- European Union 7th Framework Program
- Medical Research Council (UK)
- NS34407
- NIH
- EP/F037457/1
- Engineering and Physical Sciences Research Council (EPSRC)
- Created
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2013-01-04Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field