Complex Carbohydrates in Plant Biomass and Fungal Pathogens Investigated Using Solid-State NMR

Friday, November 5, 2021

Dr. Tuo Wang

Department of Chemistry

Louisiana State University

Friday, November 5, 2021 at 3:30 PM in Hand 1144

     Complex carbohydrates play crucial roles in energy storage, cell recognition, and structural building. The structure and assembly of these molecules are highly polymorphic and disordered in cellular environments. Here we present the recent progress in investigating two carbohydrate-rich biosystems: fungal pathogens and plant biomass. Using isotopically enriched whole-cell samples, we determined the conformation, packing, hydration, and motion of polysaccharides and associated biomolecules. Dynamic Nuclear Polarization (DNP) is required for overcoming the sensitivity limitation for probing the polymer interface. The cell wall of a major fungal pathogen Aspergillus fumigatus is found to contain hydrophobic scaffolds of chitin and α-glucans, which are enclosed in a soft matrix of β-glucans and glycoproteins. We have identified a uniquely hydrophobic and stiff cell wall architecture in those fungal cells exposed to echinocandin drugs or high salinity and those mutants devoid of major carbohydrate components. This novel mechanism helps the microbes resist external stresses and retain structural integrity. In intact plant stems, aromatic-edited experiments were conducted to understand the interaction between carbohydrates and lignin. Lignin preferentially binds to the non-flat region of xylan, which is linked to the flat-ribbon xylan domains that are coating the even surface of cellulose microfibrils. Molecules are better mixed in woody plants, resulting in stronger interactions between lignin and the cellulose-xylan junctions. The in-depth understanding of microbes’ armor and lignocellulose will facilitate the development of antifungal drugs and biofuel production technology.

Bio: Tuo Wang received his B.S. from Nankai University (China) in 2010 and started his graduate research at Iowa State University. He moved to Massachusetts Institute of Technology (MIT) in 2014 and received his PhD in Physical Chemistry in 2016 under the supervision of Dr. Mei Hong. After the postdoctoral training in Hong lab, he joined the Department of Chemistry at Louisiana State University as assistant professor in 2017 and became an associate professor in 2021. His research focuses on the structural elucidation of carbohydrate-rich biosystems. He is the recipient of NSF Career award and DOE Career award, both in 2020, Ralph E. Powe Award in 2019, and the Anatole Abragam Prize from International Society of Magnetic Resonance in 2021.

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