Effects of antimicrobial peptide indolicin on model biological membranes: A spectroscopic study

Indolicidin is a cationic antimicrobial peptide, rich in proline and tryptophan residues. It is the shortest known naturally occurring antimicrobial peptide. Although the peptide has been extensively studied, its mechanism of action is not fully understood and has not been established. This project is focused on studying the interactions between Indolicidin and model biological membranes through chemical and topographical analysis using Raman spectroscopy, Fourier Transform Infrared (FTIR), and atomic force microscopy (AFM). FTIR data revealed conformational changes to the secondary structure of the peptide in the presence of the model membranes. Raman Spectroscopy was used for confirmation and expansion of FTIR results; the data obtained from the Raman study verified the FTIR findings. Topographical analysis was performed using Atomic force microscopy (AFM). AFM images of the peptide alone showed aggregate-like structures at high concentrations while, Indolicidin-liposome systems showed micelle-like globules with an increase in surface roughness. The results gathered from this study provided new insights on the interaction of Indolicidin and served as a foundation for further investigation of the topic