Use of Modified Z-Domain Peptides to Specifically Label the Constant Region of Immunoglobulin G and VEGF

Authors

Madeline Allen, University of Nebraska-LincolnFollow

First Advisor

James W. Checco

Committee Members

Jintao Guo, David Hage

Date of this Version

10-2025

Document Type

Thesis

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science

Major: Chemistry

Under the supervision of Professor James W. Checco

Lincoln, Nebraska, October 2025

Comments

Copyright 2025, Madeline Allen. Used by permission

Abstract

Antibodies are increasingly being used in medicinal therapies due to their ability to specifically bind to a target antigen. This fundamental behavior of antibodies has been used as a key component in drug development to address common problems with traditional drug molecules such as off-targeting, fast drug clearance, and low efficacy. This thesis provides some background into how antibodies can be used as potential treatments for a few diseases. Chapter 1 begins with an overview of the human immune system, and the role antibodies play within it. Then, the variety of ways in which antibodies can be used as medicinal treatments is discussed. One of these methods is antibody conjugation (also known as antibody labeling), in which a ligand can be covalently bound to an antibody. Some common issues with the current methods of antibody labeling are explored, and potential solutions are also addressed. A potential solution to some of the problems with antibody labeling is using antibodies and ligands with affinity for one another, with a reactive group added to the ligand for covalent bond formation. Chapter 2 is a study of proximity-guided labeling of peptides with antibodies and proteins based on literature examined and presented in Chapter 1. The Z-domain peptide, derived from the B domain of Staphylococcus aureus protein A, has affinity with IgG at the Fc region, making it a good candidate for testing the substitution of a reactive group for labeling. An additional protein system, Z-VEGF and VEGF, were also analyzed in a similar matter. While there were some successes when using proximity-guided labeling for these two systems, there still remains some uncertainty regarding the consistency of results based on the experimental method and what can be observed.

Advisor: James W. Checco