Water-mediated conformational transitions in nicotinic receptor M2 helix bundles: a molecular dynamics study.
The ion channel of the nicotinic acetylcholine receptor is a water-filled pore formed by five M2 helix segments, one from each subunit. Molecular dynamics simulations on bundles of five M2 alpha 7 helices surrounding a central column of water and with caps of water molecules at either end of the pore have been used to explore the effects of intrapore water on helix packing. Interactions of water molecules with the N-terminal polar sidechains lead to a conformational transition from right- to left-handed supercoils during these stimulations. These studies reveal that the pore formed by the bundle of M2 helices is flexible. A structural role is proposed for water molecules in determining the geometry of bundles of isolated pore-forming helices.
Laboratory of Molecular Biophysics, University of Oxford, UK.
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Sankararamakrishnan
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MS
Sansom
D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D003198:Computer Simulation; D007473:Ion Channels / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D043585:Receptor, Muscarinic M2; D011976:Receptors, Muscarinic / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D007473:Ion Channels; D043585:Receptor, Muscarinic M2; D011976:Receptors, Muscarinic; D014867:Water