Study of the Orientation of the Axis of Specific Residue in α-Helical α-Synuclein (61-95) at the Interface by pMAIRS and Langmuir Monolayer of Various Protein Segments

Abstract

Parkinson’s disease is the second most common neurodegenerative disorder and falls within a diagnostic criterion centered around motor system disorders, which is primarily the result of the loss of neuronal cells that produce dopamine.2 Dopamine is a chemical messenger whose primary role is to pass on signals from one neuronal cell to another. The area of the brain releasing dopamine is known as the Substantia Nigra. The dying cells found in this area of Parkinson’s patients are riddled with Lewy bodies.2 Further investigation of these Lewy bodies revealed a major protein component known as α-synuclein, a protein that consists of 140 amino acids. The sequence of α-synuclein can be divided into three distinct domains, namely, the N-terminus domain, the hydrophobic domain, and the C-terminus domain. The hydrophobic domain (also known as the non-amyloid component domain) has been of utmost importance due to the disordered self-assembly behavior.5 In this thesis, the nonamyloid-bet component (NAC) is investigated by p-polarized multiple-angle incidence resolution spectroscopy (pMAIRS), which can be used to detect the orientation of various vibrations in ultrathin films (such as monolayer). The overall orientation of NAC in monolayer structure has been accurately determined. In addition, 13C isotopic label has been introduced into NAC, and the orientation can even be addressed in residue level by pMAIRS. Finally, the Langmuir Monolayer technique was used to the test stability of the monolayer of the various segment peptides of NAC.