This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
Proteins are among the important macromolecules in living systems, with diverse biological functions and properties that make them greatly interesting to study in both structure and function. The chemical synthesis of proteins allows researchers to incorporate a wide variety of post-translation modifications that can diversify protein functions. It also allows…
Proteins are among the important macromolecules in living systems, with diverse biological functions and properties that make them greatly interesting to study in both structure and function. The chemical synthesis of proteins allows researchers to incorporate a wide variety of post-translation modifications that can diversify protein functions. It also allows the incorporation of many noncanonical amino acids that enable the study of protein structure and function, as well as the control of their activity in living cells. The work presented in this dissertation focuses on two DNA-templated chemical synthesis approaches for the synthesis of proteins: i) DNA-templated native chemical ligation (NCL), and ii) DNA-templated click chemistry. NCL and its extended version has been used as a powerful tool to obtain proteins; however, it still struggles to make longer proteins due to aggregation and poor yield. To address these issues, a DNA-templated approach is being developed where two peptide fragments are brought into proximity by an oligonucleotide to facilitate the NCL reaction. The sequential ligation of the peptide fragments will result in full-length proteins with increased yield and improved solubility. This research involves synthesis of small molecule auxiliaries, thioester peptides, DNA-peptide conjugates, and ligation of peptides through NCL. This method has the potential to be applied to synthesize large hydrophobic proteins.
A DNA-templated click chemistry method was also reported where duplex DNA was utilized as a template for enhancing the copper click reaction between peptide fragments into functional mini-proteins. As a proof of principle, peptide fragments were synthesized with click functional groups and conjugated with distinct DNA handles through a disulfide exchange bioconjugation reaction. The DNA-peptide conjugates were assembled with the template to bring the two peptides into proximity and enhance the effective molarities of the functional groups. The peptides were coupled efficiently using a copper click reaction. The designed DNA-templated method is being implemented to synthesize a designed mini-protein (called LCB1), which can bind tightly to the spike protein of SARS-CoV-2 and inhibit its interaction with the human angiotensin-converting enzyme 2 (ACE2) receptor. This method allows researchers to introduce multiple non-natural amino acids in the protein and has the potential to extend to larger proteins, synthetic polymers, and DNA-peptide biomaterials.
