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MS (Master of Science)
Date of Award
Committee Chair or Co-Chairs
Cecilia A. McIntosh
Aruna Kilaru, Shivakumar Devaiah
Flavonoids are secondary metabolites that are important in plant defense, protection, and human health. Most naturally-occurring flavonoids are found in glucosylated forms. Glucosyltransferases catalyze the transfer of glucose from high-energy sugar donors to an acceptor molecule. The grapefruit flavonol-specific 3-O-glucosyltransferase (F3-O-GT) is highly substrate and regio-specific. The goal of this research is to unravel the amino acid residues responsible for the grapefruit enzyme’s rigid specificity, while attempting to alter the regiospecific glucosylation pattern through site-directed mutagenesis and homology modeling. This research tested the hypothesis that substitution of potential key amino acid residues within the grapefruit Cp-F3-O-GT with position equivalent residues within F7-O-GTs would alter the 3-O-glucosylation of the enzyme. Results reveal that specific single point mutations of residues are capable of abolishing enzymatic activity. Recombinant mutant G392E retained activity and showed an increased affinity for kaempferol relative to the wild-type; however, the rigid regiospecific glucosylation pattern of the enzyme was retained.
Thesis - restricted
Adepoju, Olusegun Adeboye, "Using Site-Directed Mutagenesis to Determine Impact of Amino Acid Substitution on Substrate and Regiospecificity of Grapefruit Flavonol Specific 3-O-Glucosyltransferase" (2014). Electronic Theses and Dissertations. Paper 2404. https://dc.etsu.edu/etd/2404
Copyright by the authors.