| Mass spectrometry has revolutionized the way researchers analyze chemical compounds. The most dramatic effect occurred during the last 25 years with the advent of Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). The high resolution, mass accuracy, and sensitivity of the technique made it popular for complex protein applications in the field of life sciences. These three factors have been utilized in this dissertation to observe protein-protein interactions, to identify protein(s) from complex mixtures, and to enhance our understanding of cell-cell interactions at the molecular level.; Two different protein-protein interaction systems (assembly of HIV-1 capsid proteins and complex formation of fibrillarin and Nop5p) were characterized by solution phase hydrogen-deuterium exchange methodology coupled with FT-ICR MS. Binding surfaces of these proteins were elucidated and several novel interaction sites, not previously documented by any other scientific techniques, were identified.; The interactions of microglia and cancerous glioma cells in the central nervous system were examined at the cellular level by cell cultures and at the molecular level by FT-ICR MS. Increased growth and induced non-differentiation of microglia by glioma cells were observed. Several secreted proteins from these cell lines were identified. Protein expression differences between differentiated and non-differentiated microglia within the nucleus were determined by 2D gel electrophoresis coupled with FT-ICR MS.; This dissertation also contains two chapters (online LC optimization and development of an offline LC method) concerning method developments for hydrogen-deuterium exchange experiments coupled to FT-ICR MS for elucidation of protein-protein interactions. The advantages of FT-ICR MS have successfully been shown to be applicable to protein research for determination of protein identities and for characterization of protein-protein interactions. |
