Interfacial Proteins and Peptides Studied Using Sum Frequency Generation Vibrational Spectroscopy

摘要

Interfacial structures of biological molecules such as proteins and peptides play crucial roles in a variety of biological applications and processes such as antimicrobial selectivity, membrane protein activity, biocompatibility, and biosensing. Therefore it is important to understand structural information such as orientations of interfacial proteins and peptides. The a-helix and b-sheet structures are the two most common protein secondary structures. We have developed methods to quantify the orientations of interfacial a-helix, 310-helix, and b-sheet structures using Sum Frequency Generation (SFG) vibrational spectroscopy, supplemented by Attenuated Total Reflectance Fourier Transformation Infrared Spectroscopy (ATR-FTIR).~(1-4) Using these methods, we have successfully deduced orientations of melittin,5 magainin 2,6 alamethicin,7 G-protein,8 fibrinogen,9 and tachyplesin I4 at various interfaces in situ in real time.