Coherent multidimensional infrared spectroscopy : application to the study of biomolecules under oxidative stress

• Main Author: Gierakowski, Lays Rezende Valim
• Other Authors: Klug, David ; Ces, Oscar ; Willison, Keith
• Published: Imperial College London 2017
• Subjects: 540
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.754728

There is a growing body of evidence which suggests post-translational modifications occurring under oxidative stress (oxPTMs) play an important role in both human health and disease. The focus of the work described in this thesis has been on the use of coherent multidimensional spectroscopy (CMDS) to perform detection and quantification of oxPTMs in a label-free and non-destructive manner. Electron-Vibration-Vibration (EVV) two-dimensional infrared (2DIR) spectroscopy is a CMDS technique which is able to directly observe intra- and intermolecular interactions. As a result, EVV 2DIR spectroscopy is particularly useful for characterising (oxPTMs). EVV 2DIR spectroscopy employs one near-IR and two mid-IR picosecond excitation beams to probe vibrational couplings in a sample via a four-wave mixing process. This results in the spread of vibrational coupling information across two dimensions, which leads to spectral decongestion and the ability to directly analyse vibrational modes within complex molecules, such as proteins. Here, tyrosine (Tyr) nitration is used as a study model due to its importance in inflammatory diseases, amongst other pathologies. Results are presented for various nitration models and will demonstrate EVV 2DIR spectroscopy's ability to identify, relatively quantify and characterise the effect of nitration of tyrosine side-chains.