Sum frequency generation (SFG) vibrational spectroscopy has been applied to study peptides associated with cell membranes. Results on two peptides, Pep-1 and LL-37 will be presented. Pep-1 is a cell penetrating peptide (CPP). We deduced the membrane orientations of Pep-1 on gel-phase and liquid-phase lipid bilayers at different peptide solution concentrations. This study unveiled the importance of lipid viscosity on CPP translocation, forming a foundation for further investigation of Pep-1 with peptide/proteins cargos. We developed SFG orientation analysis methodology to study LL-37, which is a bent helix. SFG experiments showed that LL-37 can interact with both zwitterionic and negatively-charged lipid bilayers but with different interaction patterns. This work shows that SFG can distinguish the subtle structural variance of biological molecules. This research provides a basis for future studies on various antimicrobial peptides (AMPs), helping design AMPs with better selectivity and activity to overcome drug resistance presented by bacteria.

Study peptide-membrane interactions by sum frequency generation spectroscopy

244th National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.