Chem501 Fall Seminar

Speaker: Dr. Elsa Yan

Professor 

Department of Chemistry

Yale University

UT Host: Dr. Tessa Calhoun

Title:  “Probing Hydration Structures of Biomolecules at Interfaces”

Abstract:

Understanding the role of water in biological processes remains a central challenge in the life sciences. Water structures in hydration shells of biomolecules are difficult to study in situ due to overwhelming background from aqueous environments. Biological interfaces introduce additional complexity because hydrogen bonding network of water is terminated abruptly at interfaces and thus biomolecular hydration differs at interfaces compared to bulk solution.  We combine experimental and computational methods of chiral vibrational sum frequency generation (chiral SFG) spectroscopy to study protein and DNA. We show that chiral SFG signals of water O-H stretches comes from the first hydration shells of these biomolecules. We further investigate mirror-image secondary structures formed by the (L-) and (D-) forms of the biomolecules and observe that each pair of the mirror-image structures generates chiral water signals with opposite signs. Hence, the biomolecules transfer their chirality to the surrounding water solvent. This transfer of chirality has an important implication – a complete description of chirality of biomacromolecules must include their hydration shells. This work presents new possibilities of using chiral SFG to address grand research challenges in biology, including the molecular origins of homochirality in life.

Bio:   

Elsa Yan was born and grew up in Hong Kong, graduating from the Chinese University of Hong Kong. She obtained her Ph.D. at Columbia University, working with Kenneth Eisenthal on nonlinear optics and surface sciences. Then she was a postdoctoral fellow in Richard Mathies's lab at UC Berkeley and a visiting fellow in Thomas Sakmar's lab at the Rockefeller University. Subsequently, she joined The Rockefeller University as Research Assistant Professor. In 2007, she became an Assistant Professor of Chemistry at Yale and was promoted to full professor in 2014. She was the recipient of the NSF CAREER Award, The Greer Memorial Prize for Achievement in Research, etc.