Molecular dynamics simulations of a lipovitellin-derived amphiphilic β-sheet homologous to apoB-100 β-sheets at a hydrophobic decane–water interface

Lipovitellin, an egg-yolk lipoprotein, transports lipids in a pocket surrounded by amphiphilic β-sheets. Its X-ray structure provides possibilities to study interactions between lipophilic β-sheets and lipids at the atomic level. Here, we studied a 67-residue-long amphiphilic β-sheet of lipovitellin previously suggested a suitable working model for studies of the lipid-binding behaviour of amphiphilic β-sheet regions in apolipoprotein B-100 (apoB-100). We performed four molecular dynamics simulations with different starting configurations to define characteristics of the amphiphilic β-sheet model at a decane–water interface. In each simulation the model β-sheet bound keenly to the decane layer via its hydrophobic surface. The structural profiles showed unchanged secondary structure of the β-sheet during the attachment. Also, aromatic side chains, especially tryptophans and tyrosines, mediated the attachment to the hydrophobic layer and influenced the orientation of the decane molecules that are in contact with the β-sheet. In conclusion, the present simulations reveal high affinity of a lipovitellin-derived amphiphilic β-sheet to a hydrophobic decane layer. They lay thereby the basis for further studies of the interaction between amphiphilic β-sheets and lipids in complex molecular systems, like LDL particles, in which the large apoB-100 is the main protein component.