04/22/2019
Dr. Alexander Ivanov
Associate Professor, Department of Chemistry & Chemical Biology
Northeastern University
Improved analytical strategies for proteomic profiling of limited samples using ultra-low flow separations coupled to mass spectrometry.
Deep proteomic profiling of limited samples (e.g., rare cells, microneedle biopsies, extracellular vesicles (EVs) isolated from minute volumes of physiological fluids, i.e., liquid biopsies, or even single cells) and especially, characterization of post-translational modifications, e.g., glycosylation, of such specimens have been a major challenge because of very low abundance and high heterogeneity in biological matrices. With the advent of more powerful separation techniques coupled to more sensitive, higher duty cycle mass spectrometers, analysis of such limited samples is getting more feasible. However, each step of the analytical workflow, including sample preparation, separation, interfacing with MS, MS data acquisition, and data analysis, requires additional advancements and flawless integration to enable deep proteomic profiling of such scarce samples. In this presentation, I will overview our recent studies where we investigated alternative approaches to enhance the sensitivity and depth of glycomic and proteomic profiling of several types of limited biological specimens in comparison to conventional techniques.
April 24th, 2019
3:30 pm MC224
Coffee and cookies will be provided!
04/09/2019
Dr. Peter Sues
Assistant Professor, Department of Chemistry
Kansas State University
Exploring Redox Active “Pacman” Ligands for Renewable Energy Applications
Storing the energy harvested from intermittent renewable sources in chemical bonds is an important part of creating a sustainable energy economy. Abundant small molecules, such as N2, O2, CO2, H2¬O, etc., will play a pivotal role in this area as their reduction and oxidation will be key in generating power on an as-needed basis. Activating these substrates, however, is a kinetically challenging endeavour that requires multi-electron and multi-proton processes. Very few homogeneous catalysts are capable of effecting these transformations, and those that can largely rely on rare and expensive platinum group metals. Natural systems, on the other hand, can activate small molecules efficiently using base metals. This is achieved through the use of multiple metal centers working in concert. Additionally, metalloenzymes are adept at controlling the orientation of small molecule binding and at protecting reactive intermediates by providing a sheltered active site for chemical transformations. Using natural systems as inspiration, we envision utilizing multiple metal centers to activate small molecules through cooperative, multi-electron mechanisms. To do this, new ligand architectures are needed. Our group uses cofacial calixpyrroles as they are synthetically facile and share some of the same characteristics as metalloenzymes: they can optimize the orientation of small molecule binding and increase catalyst stability by sheltering reactive intermediates in a supramolecular “catalytic cleft”. This presentation will explore the synthesis of new calixpyrrole ligands and metal complexes.
April 10th, 2019
3:30 pm MC224
Coffee and cookies will be provided!
