A fundamental principle of biomedicine is that small molecules can bind to specific receptors to trigger physiological responses. We seek to understand the energetic nature of the molecular events that occur at the neurotransmitter binding sites of the neuromuscular acetylcholine receptor when this channel 'gates'between non-conducting and ion-conducting conformations. This knowledge will help us understand the biophysical mechanisms of ligand-protein complexes, and will advance our ability to design new drugs for nicotinic (and other) receptors. Structure-based drug discovery should incorporate the fact that drug action depends on the differential binding of ligands to inactive vs. active conformations of a receptor. To address this point we will use single-channel electrophysiology and kinetic analysis to study unliganded gating, which will allow us to measure all of the salient activation equilibrium constants and to ascertain the energetic contributions of the side chains at each of the two transmitter binding sites. We will also estimate differential binding energies for small ligand probes, in both wild type and mutant receptors. Eventually, this knowledge will be used to engineer acetylcholine receptors that respond predictably to arbitrary ligands.
The experiments outlined in this project establish the fundamental principles for engineering a protein to respond in predictable ways to specific drugs. These principles can be applied to the development of new pharmaceuticals, and to understanding the mechanism by which a drug causes a protein to change shape.
|Nayak, Tapan K; Auerbach, Anthony (2017) Cyclic activation of endplate acetylcholine receptors. Proc Natl Acad Sci U S A 114:11914-11919|
|Gupta, Shaweta; Chakraborty, Srirupa; Vij, Ridhima et al. (2017) A mechanism for acetylcholine receptor gating based on structure, coupling, phi, and flip. J Gen Physiol 149:85-103|
|Bruhova, Iva; Auerbach, Anthony (2017) Molecular recognition at cholinergic synapses: acetylcholine versus choline. J Physiol 595:1253-1261|
|Nayak, Tapan Kumar; Chakraborty, Srirupa; Zheng, Wenjun et al. (2016) Structural correlates of affinity in fetal versus adult endplate nicotinic receptors. Nat Commun 7:11352|
|Auerbach, Anthony (2016) Dose-Response Analysis When There Is a Correlation between Affinity and Efficacy. Mol Pharmacol 89:297-302|
|Vij, Ridhima; Purohit, Prasad; Auerbach, Anthony (2015) Modal affinities of endplate acetylcholine receptors caused by loop C mutations. J Gen Physiol 146:375-86|
|Auerbach, Anthony (2015) Activation of endplate nicotinic acetylcholine receptors by agonists. Biochem Pharmacol 97:601-608|
|Purohit, Prasad; Chakraborty, Srirupa; Auerbach, Anthony (2015) Function of the M1 ?-helix in endplate receptor activation and desensitization. J Physiol 593:2851-66|
|Auerbach, Anthony (2015) Agonist activation of a nicotinic acetylcholine receptor. Neuropharmacology 96:150-6|
|Purohit, Prasad; Bruhova, Iva; Gupta, Shaweta et al. (2014) Catch-and-hold activation of muscle acetylcholine receptors having transmitter binding site mutations. Biophys J 107:88-99|
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