Chemistry Proposal Defense — Fatima Obe, Chemistry Graduate Student

About the event

Title: Digital Tandem Mass Filters for Native Spray Analysis of Proteins and Protein Complexes

Abstract:
Proteins and their complexes are an extremely important class of macromolecules that are involved in almost all functional roles needed to sustain life.1,2 Be it as digestive enzymes helping to facilitate chemical reactions, as antibodies supporting immune systems or as hormones coordinating body functions, proteins are invaluable when it comes to human survival. As such, it is important to understand the structural details of these molecules. The initial mass spectrometry method used in protein studies involves predigesting the protein molecule followed by measurement of a representative peptide segment, a method known as “bottom-up proteomics”. This method lacks the ability to differentiate the protein analyte from its post-translational modifications (PTMs) thereby obscuring the detailed information about the original molecule.3,4 In this research, a “native” mass spectrometric technique which allows the analysis of intact proteins in their natural charge states,5-7 will be employed in the analysis of large proteins such as carbonic anhydrase (CA, 29 kDa); hemoglobin (Hgb, 64.5 kDa); bovine serum albumin (BSA, 66.4 kDa) etc.,  and protein complexes such as carbonic anhydrase II-chlorothiazide and adenylate kinase-ATP. The analysis will be conducted with a novel digitally operated tandem quadrupole mass filters (DTMF) with an electrospray ionization source. The first part of the project will focus on the development of the instrument while the rest of the work will apply the new instrument in the studies of the large proteins and complexes. The DTMF is expected to afford better resolving power as well as better ion transmission than the commercial sinusoidally operated quadrupole instruments. In this presentation, I will be describing the instrumental set ups and the operating principles of the DTMF. Some preliminary results already obtained will also be presented.

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