RT Journal Article
SR Electronic
T1 NMR Analysis of the interaction of Ethanol With the Nicotinic Acetylcholine Receptor
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 139717
DO 10.1101/139717
A1 David Naugler
A1 Robert J. Cushley
A1 Ian Clark-Lewis
YR 2017
UL http://biorxiv.org/content/early/2017/07/15/139717.abstract
AB Ethanol exerts its actions in the central and peripheral nervous systems through the direct interactions with several proteins, including ligand-gated ion channels such as the nicotinic acetylcholine receptor (nAChR). The binding interaction between ethanol and sodium cholate solubilized nicotinic acetylcholine receptor protein can be detected through either NMR line broadening or T1 titration. In this paper, we examine the use of weighted Navon T1p analysis of T1 titration data for the estimation of the dissociation constant of ethanol for the nAChR. We show that Navon T1p analysis underestimates binding affinity. The application of rigorous limits for confidence intervals within a nonlinear regression analysis of this data provides a best estimate of Kd = 55 μM at 4 °C. within an unsymmetrical 90% confidence interval of [0.5, 440 μM]. Accordingly, the best estimate of the binding free energy is ΔG0, = −5.4 Kcal/mole within a 90% confidence interval of [−8.0, −4.3 Kcal/mole],relative to conventional standard states.