Molecular dynamics simulation of Bombolitin II in the dipalmitoylphosphatidylcholine membrane bilayer.

The orientation behavior of Bombolitin II (BLT2) in the dipalmitoylphosphatidylcholine membrane bilayer was investigated by using molecular-dynamics simulation. During the 20-ns simulation, the BLT2 began to tilt and finally reached the angle of 51° from the membrane-normal. The structure of the peptide formed the amphipathic α-helical structure during the entire simulation time. The peptide tilts with its hydrophobic side faced to the hydrophobic core of the bilayer. We analyzed the mechanism of the tilting behavior of the peptide associated with the membrane in detail. The analysis showed that the hydrogen-bond interaction and the electrostatic interaction were found to exist between Lys(12) and a lipid molecule. These interactions are considered to work as an important factor in tilting the peptide to the membrane-normal.