Title: "Reactive Sulfur Species: From Redox Biology to Peptide Editing"

Ming Xian, Jesse Houghton Metcalf Professor of Chemistry

Brown University

Host: Brett VanVeller

Abstract: Hydrogen sulfide (H₂S) and related reactive sulfur species (RSS) are important regulatory molecules in redox biology, with diverse physiological effects ranging from anti-inflammatory and antioxidant activities to modulation of protein function. Advancing the biological investigation of these species requires chemical tools that can generate or remove specific sulfur species under biologically relevant conditions while minimizing unwanted bioactive byproducts. In this presentation, I will discuss our efforts to develop carbohydrate-based RSS donors and related chemical tools, including thiosaccharides, thioglucose-derived polysulfides and persulfides, and selenoglucose derivatives. We found that (1) glucose oxidase catalyzes the oxidation of thioglucose to generate both H₂S and H₂O₂, which together promote protein persulfidation; (2) thioglucose and other thiosaccharides can serve as slow-releasing H₂S donors; (3) thioglucose tetrasulfide is an effective H₂S donor and can also function as a persulfide precursor; and (4) glucose-derived diselenides act as H₂S scavengers and potential selenium donors. Finally, I will present our recent work using photo chemistry to convert cysteine-containing peptides into thiazoles through thioaldehyde formation, illustrating how reactive sulfur chemistry can be harnessed for peptide editing.

Bio: Ming Xian is the Jesse Houghton Metcalf Professor of Chemistry at Brown University. His research sits at the interface of chemistry and biology, with a particular focus on reactive sulfur species, including hydrogen sulfide, persulfides, and S-nitrosothiols, and their roles in biological systems. Dr. Xian develops new chemical tools, probes, and synthetic methods to better understand these important signaling molecules and their functions in health and disease. He received his B.S. from Nankai University and his Ph.D. from Wayne State University, followed by postdoctoral training at the University of Pennsylvania. Before joining Brown University in 2020, he was a faculty member at Washington State University, where he was named the inaugural Ralph G. Yount Distinguished Professor in Chemical Biology.

Ming Xian | Chemistry | Brown University