Membrane Induced Folding of a cationic ß-hairpin

We recently developed a minimalistic coarse-grained model for lipids and peptides by using the Drude oscillator approach to model the  electrostatic component of Hydrogen bonds. With our models, we were able to simulate membrane induced folding of a cationic ß-hairpin, SVS-1 on POPS model bilayer.

Here is a short animation:

MSO8AAFC3CC173Colors: Hydrophobic tails: green; Serine: cyan; Ester: purple; Phosphate: tan;Peptide backbone: black;LYS: crimson and VAL side chain: pink. All bead sizes exaggerated for clarity. 

You can see the peptide fold and freely diffuse on the surface of the membrane.

Another cool thing is that we find membrane-induced peptide folding to be driven by both (a) cooperativity in peptide self interaction (something that is expected for folding) and (b) cooperativity in membrane-peptide interaction (which is pretty cool). For more, check out our latest article.

Water Transport in Membranes

Here is a movie I made today, it shows water transport through a membrane inserted peptide. All the colored beads represent lipid head groups, the peptide backbone is in black, the orange beads represent LYS side chains and the cyan bead is a water. You can see the water molecule move from one LYS residue to another and slowly to the other leaflet.

It is nothing new and processes like these have been observed before, but I think it is very cool to watch the animation.

Also, sizes are exaggerated for clearer depiction.

pore1.gif