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Membrane Bound Hydraphiles Facilitate Cation Translocation

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posted on 08.04.2004, 00:00 by Goundla Srinivas, Carlos F. Lopez, Michael L. Klein
The mechanism of hydraphile assisted cation translocation across a lipid bilayer is investigated by means of coarse-grain molecular dynamics simulations. We find that hydraphiles with appropriate length adopt a channel-like conformation in agreement with recent experimental studies. In trans membrane conformation, hydraphiles assist ion-passage across the bilayer via a mechanism that is found to be rare but effective. The observed time for ion translocation is approximately 0.3 ns. Trajectory studies reveal that the translocating ion shows relatively less mobility in the vicinity of the hydraphile ring when compared to that in bulk water. The present coarse grain simulations confirmed that hydraphile molecules with a chain length matching the bilayer thickness can assist ion transport, whereas hydraphiles having a shorter or longer chain length fail to do so. In addition, the present simulation study underscores the necessity of a polar central relay for a molecule to act as a translocation facilitator.