OCCI Seminar Series: Professor Ann English

• In-Person event
• 447, Tory Building, Carleton University
• 1125 Colonel By Drive, Ottawa, ON, K1S 5B6

How mass spectrometry empowers the study of metalloprotein redox reactions  in the test tube and cell

Professor Ann English
Department of Chemistry and Biochemistry
Concordia University

Close to 40 years ago the Gray group at Caltech “ruthenated” cytochrome c with Ru(NH3)5 to study electron transfer through the protein matrix. Preparation and characterization of this derivative took close to six years to complete. Since then, the development of protein mass spectrometry (MS) has enabled us to characterize ruthenated derivatives of cytochrome c peroxidase (Ccp1) and myoglobin in a day. Furthermore, using LC-MS/MS, we have extensively profiled oxidative posttranslational modifications (PTMs) of Ccp1 induced by H2O2 in yeast cells. Mapping the residues oxidized reveals that hole hopping protects Ccp1’s heme from irreversible oxidative damage but weakens the heme-protein interaction. This enables heme recruitment for maturation of apocatalase (Cta1), a better H2O2 scavenging enzyme than Ccp1. Such unprecedented heme mobilization is illustrative of the new redox reactions of metalloproteins emerging from their analyses by high-performance LC-MS/MS