Sum frequency generation (SFG) vibrational spectroscopy has been applied to determine orientations of peptides and proteins in model cell membranes in situ, supplemented by attenuated total reflectance (ATR) Fourier transform infrared spectroscopy. Various peptides including antimicrobial peptides (AMPs) with various secondary structures and cell penetrating peptides (CPPs) were investigated. It was found that various peptides interact with different model cell membranes, e.g., model bacterial cell membranes and model mammalian cell membranes quite differently. The membrane orientations of various AMPs are dependent on the peptide solution concentrations, and can be successfully correlated to different antimicrobial modes of action. Membrane orientations of various proteins, such as cytochrome b5, Gbg-GRK2 complex, and Gabg complex have also been successfully determined.

Determination of membrane orientation of peptides and proteins using nonlinear optical spectroscopy

244th National Meeting (2012)

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