The vast majority of theses in this collection are open access and freely available. There are a small number of theses that have access restricted to the WWU campus. For off-campus access to a thesis labeled "Campus Only Access," please log in here with your WWU universal ID, or talk to your librarian about requesting the restricted thesis through interlibrary loan.
Date Permissions Signed
Date of Award
Master of Science (MS)
Spiegel, P. Clint
Antos, John M.
Polymerized hemoglobin (poly-Hb) molecules have been shown to have reduced toxicity compared to cell-free hemoglobins when transfused intravenously. Poly-Hbs are typically generated with non-specific crosslinking agents that yield a product that is polydisperse in molecular weight. We propose a chemoenzymatic approach to generate poly-Hb of defined molecular weight. The proposed method employs the site-specific ligation reaction of the sortase A enzyme from S. aureus. A Hb mutant previously developed in our lab has been “sortagged” – modified by adding either the sortase recognition sequence (LPXTG) to the C-terminus of the α-subunit or a tetraglycine motif (GGGG) to the N-terminus. We show here that Hb subunits can be ligated directly by sortase A, using a mixture of substrate tagged (LPXTG) and nucleophile tagged (poly-G) Hbs. Additionally, using a novel approach for crosslinking Hb subunits using sortase A, we have generated a di-α construct that is functionalized with a strained cycloalkyne through an unnatural C-to-C fusion of sortagged α-subunits using a bifunctional sortase nucleophile peptide. We show that cycloalkyne-modified Hb molecules can be covalently linked to an azide functionalized fluorescein, using the well-established method of Huisgen cycloaddition. The work presented here establishes the feasibility of generating a monodisperse poly-Hb using azide decorated scaffolds.
HBOCs, blood substitute, hemoglobin-based oxygen carriers, polymerized hemoglobins, poly-Hbs, RBC substitute, red blood cell substitute
Western Washington University
Subject – LCSH
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.
Sigurjonsson, Johann, "A Chemoenzymatic Approach to the Synthesis of Hemoglobin Oligomers" (2018). WWU Graduate School Collection. 750.