Molecular dynamics simulations of ion channels formed by bundles of amphipathic α-helical peptides |
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Authors: | P Mitton M S P Sansom |
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Institution: | (1) Laboratory of Molecular Biophysics, The Rex Richards Building, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK (Fax: +44 1865-51 04 54, e-mail: markbiop.ox.ac.uk), GB |
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Abstract: | Ion channels may be formed by self-assembly of amphipathic α-helical peptides into parallel helix bundles. The transbilayer pores formed by such peptides contain extended columns of
water molecules, the properties of which may differ from those of water in its bulk state. The de novo designed peptides of
DeGrado et al., which contain only leucine and serine residues, are considered as a simple example of such channels. Molecular
dynamics simulations of peptide helix bundles with water molecules within and at the mouths of their pores are used to refine
such models and to investigate the properties of intra-pore water. The translational and rotational mobility of water molecules
within the pores are reduced relative to bulk water. Furthermore, intra-pore waters orient themselves with their dipoles anti-parallel
to the helix dipoles, as do the hydroxyl groups of serine residues. Comparison of approximate predictions of ionic conductances
with experimental values provides support for the validity of these models.
Received: 23 April 1996 / Accepted: 7 August 1996 |
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Keywords: | Ion channel Water Molecular dynamics Dipole α -helix Peptide |
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