Molecular interactions between peptides and cell membrane govern biological functions of these peptides. Since a large variety of ions is usually present in biological systems, knowledge about such interactions in aqueous environments is crucial to recognize the nature of driving force and weak molecular interaction behind such interactions. In this talk, sum frequency generation vibrational spectroscopy (SFG-VS) has been applied to characterize the ionic effects on the interaction between peptides(mastoparan and melittin) and modeling cell membrane. It was found that Kosmotropic ions (such as H2PO4-, SO42-) can greatly increase the number of the peptide molecules that inserted into the fluid-phase lipid bilayer while chaotropic ions (such as Cl- and I-) show opposite role. The ions of H2PO4- and SO42- can even promote the mastoparan molecules insert into positively-charged fluid-phase lipid bilayer. However, in the gel-phase lipid bilayer, Kosmotropic and chaotropic ions both decrease the number of the membrane-associated peptide molecules.

Molecular-level insights into ionic effects on the interaction between peptides and modeling cell membrane

244th National Meeting (2012)

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