Off-campus ETSU users: To download "Campus Only" theses, please use the following link to log in to our proxy server with your ETSU username and password.

Non-ETSU users: Please talk to your librarian about requesting this thesis through interlibrary loan.

Degree Name

MS (Master of Science)

Program

Biology

Date of Award

12-2014

Committee Chair or Co-Chairs

Cecilia McIntosh

Committee Members

Shivakumar Devaiah, Aruna Kilaru

Abstract

Flavonoids are plant secondary metabolites that have significant biochemical and physiological roles. Biosynthesis of these compounds involves several modifications, most predominantly glucosylation, which is catalyzed by glucosyltransferases (GTs). A signature amino acid sequence, the PSPG box, is used to identify putative clones and has been shown to be involved in UDP-glucose binding. Site-directed mutagenesis is used to answer questions regarding the structure and function of this family of enzymes, particularly what allows some GTs to be more selective towards some substrates than others. The grapefruit (Citrus paradisi) flavonol-3-O-glucosyltransferase (CpF3GT) is specific for flavonol substrates and will not glucosylate anthocyanidins. Comparison of the CpF3GT sequence with that of Vitis vinifera GT, which glucosylates both flavonols and anthocyanidins, provided the basis for the amino acid substitution of proline 145, alanine 374, and alanine 375 in CpF3GT to threonine, aspartate, and glycine, respectively, to test the affect on GT’s affinity for flavonoid substrates.

Document Type

Thesis - Campus Only

Copyright

Copyright by the authors.

Share

COinS