Fast lipid disorientation at the onset of membrane fusion revealed by molecular dynamics simulations.
Membrane fusion is a key event in vesicular trafficking in every cell, and many fusion-related proteins have been identified. However, how the actual fusion event occurs has not been elucidated. By using molecular dynamics simulations we found that when even a small region of two membranes is closely apposed such that only a limited number of water molecules remain in the apposed area (e.g., by a fusogenic protein and thermal membrane fluctuations), dramatic lipid disorientation results within 100 ps-2 ns, which might initiate membrane fusion. Up to 12% of phospholipid molecules in the apposing layers had their alkyl chains outside the hydrophobic region, lying almost parallel to the membrane surface or protruding out of the bilayer by 2 ns after two membranes were closely apposed.
Ohta-Iino
S
S
Kusumi Membrane Organizer Project, ERATO, JST, Nagoya 460-0012, Japan.
Pasenkiewicz-Gierula
M
M
Takaoka
Y
Y
Miyagawa
H
H
Kitamura
K
K
Kusumi
A
A
D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism*; D003198:Computer Simulation; D006838:Hydrocarbons / Q000737:chemistry / Q000378:metabolism; D006860:Hydrogen Bonding; D008561:Membrane Fusion; D008563:Membrane Lipids / Q000378:metabolism*; D008958:Models, Molecular; D008968:Molecular Conformation; D055672:Static Electricity; D014867:Water / Q000378:metabolism
D006838:Hydrocarbons; D008563:Membrane Lipids; D014867:Water