Study of Protein-Protein Interactions in Septin Assembly: Multiple amphipathic helix domains cooperate in binding to the lipid membrane
Fig 3
The presence of a membrane-bound peptide modulates the positioning and orientation of the unbound peptide toward the membrane.
(A) Distribution of the Z-component of the center of mass (COM) for the unbound peptide in systems with single (orange, n = 4) and two peptides (green, n = 4). The gray curve shows the distribution of Z-positions of lipid phosphate headgroups. Left inset: MD simulation snapshot showing the single unbound peptide approaches the membrane via the C-terminus (orange). Right inset: MD simulation snapshot showing an unbound and a bound peptide. The N-terminal region of the unbound peptide can interact with the bound peptide (green). (B) Box plot of the Z-COM of residues in the system with a single unbound peptide (n = 4). The blue and red dashed lines separate the N- and C-terminal regions, respectively. (C) Box plot of the Z-COM of residues of the unbound peptide in the multiple-peptide system. The first four N-terminal residues (blue box) show a closer approach to the membrane, consistent with interaction with the membrane-bound peptide.