ASRC-CCNY Seminar Series in Biochemistry, Biophysics and Biodesign: Alexander R. Ivanov, Northeastern University

Big and small: Mass spectrometry-based studies of small cell populations, single cells, and ~1 MDa multimeric protein assemblies

Abstract    The field of proteomics research has been rapidly evolving during the last two decades. In the previous few years, the fields of single-cell proteomics and native mass spectrometry have progressed substantially. However, deep proteomic profiling of limited samples (e.g., small populations of rare cells, individual cells, microneedle biopsies, subpopulations of extracellular vesicles (EVs) isolated from minute volumes of biofluids) and especially, characterization of post-translational modifications (PTMs) and non-covalent protein interactions of intact multimeric protein complexes at such sample amount levels have been a major challenge because of very low abundance and high heterogeneity of complex biological matrices. In this presentation, I will overview a combination of advanced sample preparation, pressure- and electric field-driven ultra-low flow high-efficiency nanoscale liquid phase separations coupled to mass spectrometry (MS) via alternative interfacing techniques to evaluate the potential applicability for high sensitivity, robust and reproducible proteomic and glycomic profiling of individual cells and low ng-/sub-ng-level complex biological samples, using bottom-up, top-down, and native proteomic and PTM profiling approaches. Also, our recent progress in native MS-based structural characterization of large ~1 MDa multimeric GroEL assemblies upon complexation with nucleotides (ATPγS or ADP), GroES, and cofactors and the binding stoichiometry and kinetics of the analyzed protein complexes will be presented and discussed.