Fig. 7

Cross-sectional views of the B-YL peptide in lipid surfactant bilayers after MD simulations. Main-chain folding of the B-YL peptide is shown in the ribbon-rainbow format, with the N-terminal insertion sequence in blue, the N-terminal helix in blue-green, the turn hairpin region in green-yellow and the C-terminal helix in yellow-orange. Lipids are shown as green stick figures, while water is left out for clarity. The ribbon model for the 500 nsec B-YL conformer folds as a helix-hairpin, with the Y8, Y11 and Y34 tyrosine residues (i.e., purple stick figures) bridging the N- and C-α helices through noncovalent aromatic interactions. The axes for the N- and C-α helices are each nearly parallel to the bilayer plane. However, the N-α helix lies deeper in the bilayer subjacent to the lipid headgroup, while the C-α helix binds to the more polar lipid-water interface