Ketosterol flip flop

A movie of a ketosterol molecule undergoing a flip-flop in a lipid bilayer. To our knowledge this is the first time a sterol flip-flop has been seen in a molecular dynamics simulation. The ketosterol molecule that undergoes flip flop is given in van der Waals representation and the rest of the lipid and sterol molecules are shown using sticks. The simulation was done with explicit (SPC) water, but water is not shown in the movie for clarity.

 

Flip-flop, sometimes also called transverse diffusion, is one of the possible modes for lipid diffusion in biological membranes (lipid bilayers).

 

Ketosterol is a biological molecule which has a structure similar to cholesterol except that cholesterol's hydroxyl headgroup is replaced by a ketone group.

 

NOTE: For some reason, flickr didn't preserve the quality when converting the video. If you prefer the higher quality one, you can download it.

 

See also:

 

- Ethanol interacting with a biomembrane

- Ethanol hydrogen bonded with POPC

- Xenon molecules interacting with a lipid bilayer

 

Reference:

 

1. Replacing the cholesterol hydroxyl group by the ketone group facilitates sterol flip-flop and promotes membrane fluidity, T. Rog, L.M. Stimson, M. Pasenkiewicz-Gierula, I. Vattulainen, M. Karttunen, J. Phys. Chem. B. 112 1946-1952 (2008). dx.doi.org/10.1021/jp075078h

Done