SEMINAR

DEPARTMENT OF CHEMICAL ENGINEERING 

Macro- and Microphase Separation of Engineered Proteins with Polyelectrolytes

Professor Allie Obermeyer

Department of Chemical Engineering, Columbia University

Abstract

Protein-polyelectrolyte coacervates have shown great potential in protein purification and protein delivery. However, many proteins do not form stable complexes or do not phase separate with oppositely charged polyelectrolytes. To address this challenge, the influence of protein charge density and anisotropy on complexation and phase separation with polyelectrolytes was tested by engineering model proteins. Phase separation of the engineered proteins with strong and weak polyelectrolytes has been investigated by light scattering and optical microscopy. Importantly, short polypeptide tags were found to promote complex coacervation. The length and sequence of these polypeptides was found to impact the critical salt concentration and protein concentration in the coacervate phase. The thermodynamics of the complexation of engineered proteins with a strong polyelectrolyte was measured using isothermal calorimetry. These findings have been used to design micellar assemblies for intracellular protein delivery.

Biography

Prof. Obermeyer earned her B.S. from Rice University and her Ph.D. at the University of California, Berkeley where she was an NSF Graduate Research Fellow. She completed her postdoctoral work with Brad Olsen at Massachusetts Institute of Technology where she was an Arnold O. Beckman Postdoctoral Fellow. She started her independent career in the Chemical Engineering Department at Columbia University in January 2017. In 2019 she was the recipient of an NSF CAREER award. Broadly, her research sits at the interface of chemistry, biology, and polymer science and aims to develop new functional materials from proteins.