Dr. Julia Oktawiec

Julia Oktawiec
Materials Science& Engineering
Northwestern University
Abstract

Structural Design of Proteomimetic Materials for Gas Separations and Therapeutics

Proteins have complex structures and dynamics that influence ligand binding. These include allosteric effects and the presentation of organized arrays of functional groups. Inspired by these mechanisms, in this talk I will first describe my efforts towards proteomimetic materials that selectively capture dioxygen. This work found that coupling metal-based electron transfer with secondary coordination sphere effects in a cobalt-based metal–organic framework leads to strong and reversible adsorption of O2. Moderate-strength hydrogen bonding stabilizes a cobalt(III)- superoxo species formed upon O2 adsorption. Notably, O2-binding in this material weakens as a function of loading, as a result of negative cooperativity arising from electronic effects within the extended framework lattice. This behavior extends the tunable properties that can be used to design metal–organic frameworks for adsorption-based applications. 

In the second part of the talk, I will share the development of structural design rules for peptide brush polymers. These systems, generated by graft-through living polymerization, show promise as therapeutic agents and tandem repeat protein mimics. Prior work has focused on polymers composed from disordered peptides, and so conformational information is limited. To obtain greater insight into the structure of these systems and how it is influenced by properties of the peptide brushes, I studied a library of polymers generated from different classes of folded peptides. Spectroscopy and X-ray scattering reveals that modulation of the hydrophobicity and folding of the peptide brush plays an important role in the conformation of the polymer. Molecular dynamics simulations performed by collaborators illuminate this relationship in greater detail, corroborating experimental results. This work provides principles for the design of polymer therapeutics to bind proteins through specific structural interactions.

Julia Oktawiec

Dr. Julia Oktawiec is currently a NIH NRSA postdoctoral research scholar at Northwestern University in Prof. Nathan Gianneschi’s group focusing on the design peptide brush polymers for applications as therapeutics and proteomimetic materials. Originally from New York City, she pursued her undergraduate studies at Columbia University. She obtained her PhD at UC Berkeley under Prof. Jeffrey Long targeting bioinorganic-inspired oxygen adsorption in metal–organic frameworks, graduating in 2019. She is excited about bioinspired materials, their structural design, and mimicking the mechanisms that biology uses to accomplish complex tasks.

Hosted by Professor Ian Tonks