1 research outputs found
Dynamic Structure and Orientation of Melittin Bound to Acidic Lipid Bilayers, As Revealed by Solid-State NMR and Molecular Dynamics Simulation
Melittin is a venom
peptide that disrupts lipid bilayers at temperatures
below the liquid-crystalline to gel phase transition temperature (<i>T</i><sub>c</sub>). Notably, the ability of melittin to disrupt
acidic dimyristoylphosphatidylglycerol (DMPG) bilayers was weaker
than its ability to disrupt neutral dimyristoylphosphatidylcholine
bilayers. The structure and orientation of melittin bound to DMPG
bilayers were revealed by analyzing the <sup>13</sup>C chemical shift
anisotropy of [1-<sup>13</sup>C]-labeled melittin obtained from solid-state <sup>13</sup>C NMR spectra. <sup>13</sup>C chemical shift anisotropy showed
oscillatory shifts with the index number of residues. Analysis of
the chemical shift oscillation properties indicated that melittin
bound to a DMPG membrane adopts a bent α-helical structure with
tilt angles for the N- and C-terminal helices of −32 and +30°,
respectively. The transmembrane melittin in DMPG bilayers indicates
that the peptide protrudes toward the C-terminal direction from the
core region of the lipid bilayer to show a pseudotransmembrane bent
α-helix. Molecular dynamics simulation was performed to characterize
the structure and interaction of melittin with lipid molecules in
DMPG bilayers. The simulation results indicate that basic amino acid
residues in melittin interact strongly with lipid head groups to generate
a pseudo-transmembrane alignment. The N-terminus is located within
the lipid core region and disturbs the lower surface of the lipid
bilayer