The intrinsic energy of the gating isomerization of a neuromuscular acetylcholine receptor channel.

ABSTRACT: Nicotinic acetylcholine receptor (AChR) channels at neuromuscular synapses rarely open in the absence of agonists, but many different mutations increase the unliganded gating equilibrium constant (E0) to generate AChRs that are active constitutively. We measured E0 for two different sets of mutant combinations and by extrapolation estimated E0 for wild-type AChRs. The estimates were 7.6 and 7.8×10(-7) in adult-type mouse AChRs (-100 mV at 23°C). The values are in excellent agreement with one obtained previously by using a completely different method (6.5×10(-7), from monoliganded gating). E0 decreases with depolarization to the same extent as does the diliganded gating equilibrium constant, e-fold with ∼60 mV. We estimate that at -100 mV the intrinsic energy of the unliganded gating isomer

SUBMITTER: Nayak TK 

PROVIDER: S-EPMC3343375 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature