Ftir-Spectroscopic Analysis Of Proteins In Liquid Samples

Fourier-transform-infrared- (FTIR) spectroscopy has proved to be quite useful for protein detection at low concentrations and determination of protein secondary structures. It has been very successfully applied for detection and structure analysis of soluble and membrane proteins [1]. The surface sensitive total reflection- (ATR) technique has been particularly useful for the analysis of membrane anchored proteins [2,3,4]. Thus, secondary structure analysis of various disease related proteins like Prion Protein (PrP) or Amyloid-beta- (Aß) is achieved. Upon disease progression, these proteins undergo a structural transition from a-helix to ß-sheet conformations. The modification of the internal reflection element (IRE) renders the surface selective for specific compounds [5]. Further, ATR-spectroscopy is suitable for analysis of protein-protein interactions and their biological function in an aqueous environment. Kinetic analysis of protein-substrate interactions were performed. Additional, the orientation of proteins can also be obtained using polarized infrared radiation. Here, we provide a brief overview of current applications and the potential of the ATR-spectroscopy in the biomedical sector. References: [1] J. Ollesch et al, Prion Protein a-to-b Transition Monitored by Time-Resolved Fourier Transform Infrared Spectroscopy 2007, Applied Spectroscopy, 61, 1025-1031. [2] K. Elfrink et J. Ollesch et al, Structural changes of membrane-anchored native PrPC 2008, Proceedings of the National Academy of Sciences, 105, 10815-10819. [3] J. Güldenhaupt et al, Secondary structure of lapidated Ras bound to a lipid bilayer 2008, FEBS Journal, 275, 5910-5918. [4] P. Pinkerneil et al, Surface attached polyhistidine-tag proteins characterized by FTIR difference spectroscopy 2012, European Journal of Chemical Physics and Physical Chemistry, 13, 2649-2653. [5] Schartner J., Güldenhaupt J., Mei B., Rögner M., Muhler M., Gerwert K., Kötting C. Journal of the American Chemical Society 2013, DOI: 10.1021/ja400253.