Date of Award

Fall 9-28-2020

Semester of Degree


Document Type

Open Access Thesis

Degree Name

M.S. in Chemistry



Major Professor

Erica Majumder

Steering Committee Member

Christopher Nomura

Steering Committee Member

Liviu Movileanu

Steering Committee Member

Aaron Wolfe

Steering Committee Member

Kelsey Moody


Peptide library screening and binding surface mutagenesis are effective tools in early-stage drug development that give critical insights for evaluating biologic interactions. Prior to later- stage chemistry, manufacturing, and controls (CMC), biologic potency depends on modulating key amino acid residues affecting the affinity of the potential drug towards its target(s). Developing biologics is thus increasingly dependent on high-throughput screening (HTS) techniques that accommodate rapid iteration of many candidates. Here, I synthesized a small library of epitope peptides derived from therapeutic targets and conducted a series of fluorescence anisotropy-based screens against RPtag: a novel, super-stable, antibody-like protein scaffold with pM binding affinity. I demonstrated tunability of RPtag and highlight its potential as a novel biologic by increasing affinity towards PD-L1 peptide by orders of magnitude. Finally, I used surface plasmon resonance (SPR) to demonstrate binding between a rationally engineered RPtag mutant to recombinant PD-L1 and discuss the implications of my findings.

Available for download on Tuesday, September 28, 2021