Gating Nanodomains of the Acetylcholine Receptor » książka
Gating Nanodomains of the Acetylcholine Receptor
ISBN-13: 9783639164732 / Angielski / Miękka / 2009 / 172 str.
The nicotinic acetylcholine receptor (AChR) is a pentameric ligand-gated ion channel that can switch between ion-impermeable (closed) and ion-permeable (open) conformations. The transition state structures that link the closed and open states are largely unresolved. In this study, I used single-molecule kinetic analysis and rate-equilibrium linear free energy relationships (REFERs) to obtain information about the transition state of the gating reaction and elucidate the sequence of molecular events between the closed and open conformational states. REFER analyses of 87 mutants in the M4 transmembrane segments indicate that the M4 segment moves as single domain and in the middle of the gating reaction, with both subunits moving synchronously. Between the subunits, the sequence of M4 motions is . In the pore-lining M2 segments, I show that the two -subunits experience distinct energy barriers to gating at the equator and that the subunit motions in this region are asymmetric with regard to their reaction progress in the AChR gating conformational 'wave'. Future experiments involving a more extensive REFER analysis will provide finer details of this ion channel nanomachine."
The nicotinic acetylcholine receptor (AChR) is apentameric ligand-gated ion channel that can switchbetween ion-impermeable (closed) and ion-permeable(open) conformations. The transition state structuresthat link the closed and open states are largelyunresolved. In this study, I used single-moleculekinetic analysis and rate-equilibrium linear freeenergy relationships (REFERs) to obtain informationabout the transition state of the gating reaction andelucidate the sequence of molecular events betweenthe closed and open conformational states. REFERanalyses of 87 mutants in the M4 transmembranesegments indicate that the αM4 segment moves assingle domain and in the middle of the gatingreaction, with both α−subunits moving synchronously.Between the subunits, the sequence of M4 motions isα−ε−β. In the pore-lining M2 segments, I show thatthe two α-subunits experience distinct energybarriers to gating at the equator and that thesubunit motions in this region are asymmetric withregard to their reaction progress in the AChR gatingconformational wave. Future experiments involving amore extensive REFER analysis will provide finerdetails of this ion channel nanomachine.
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