Biomolecular Characterization via Radical Directed Dissociation

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Professor Ryan R. Julian of the University of California Riverside is supported by the Chemical Measurement and Imaging (CMI) Program in the Division of Chemistry and the Instrument Development for Biological Research (IDBR) Program in the Directorate for Biological Sciences to further develop his mass spectrometry methodologies, which were initially developed for the identification and characterization of peptides and proteins. The project will expand the scope of biomolecules to which mass spectrometry can be applied, opening up new avenues of scientific research in numerous fields including molecular biology, biochemistry and medicine. Specifically, the proposed methods for improved oligosaccharide analysis are destined to be broadly useful as these are biologically and biomedically important molecules for which existing tools are only moderately useful. In this context, the project promises to enhance our understanding of life processes. In the course of conducting this research, graduate and undergraduate students will acquire valuable skills in bioanalytical technologies, mass spectrometry and chemical synthesis. The PI will actively participate in UCR programs (GradEDge and AGEP) that are focused on the successful advancement of minority students within the graduate school, and the research team will participate in science fairs and science demonstrations at local K-12 schoolsThe project is organized in three specific objectives: (1) to explore the utility of radical directed dissociation (RDD) for the elucidation of the structure of oligosaccharides and to delineate the unique fragmentation pathways that RDD produce in oligosaccharides. The focus of this objective will be on a range of targets including glycosaminoglycans, O- and N- linked glycans and glycopeptides; (2) to use RDD to identify antioxidant peptides and determine their solution phase antioxidant capacity. The inherent antioxidant capacity of biologically relevant proteins and the factors that influence antioxidant capacity will be investigated, and a combination of sequence substitution and MS/MS experiments will be used to reveal information about how radicals are sequestered; and (3) to utilize photocaged covalent labels and photochemistry to map the higher order solution phase structure of proteins, in particular multiprotein complexes.