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Title: Functional analysis of UDP-sugar : sterol glucosyltransferases
Author: Malik, Vatsala
ISNI:       0000 0004 2720 9138
Awarding Body: Northumbria University
Current Institution: Northumbria University
Date of Award: 2011
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Glycosyltransferases (GTs) are essential for the biosynthesis and diversification of many therapeutically important natural products. Of these, UDP-sugar: sterol glucosyltransferases (UGTs) ( catalyse the synthesis of therapeutically important steryl glycosides (SGs). Guided by the sequence similarity with a previously characterised N-terminally truncated UGT from Saccharomyces cerevisiae (UGT51), this study reports the cloning of the gene fragment encoding the C-terminal catalytic domains from related yeasts and the expression and characterisation of their encoded products produced. N-terminally histidine tagged proteins were purified for in vitro assays against a panel of sterol and steroidal acceptors. Liquid chromatography-mass spectrometry (LC-MS) and kinetic analysis led to the successful characterisation of two novel UGTs from Pichia angusta and Kluyveromyces lactis. In addition, testosterone was shown to be utilized by all UGTs, including the previously characterised S. cerevisiae UGT51. Random mutagenesis of UGTs and homology modelling of the S. cerevisiae UGT revealed structural similarities with family 1 bacterial glycopeptide GTs. Given the structural and mechanistic similarities among GT family 1 UGTs, this approach may provide a template for genetic manipulation of novel UGTs from other members of the GT superfamily with a better understanding of catalytic domains and for broadening their scope in drug development. It may also aid the development of a generic process in the synthesis of SGs.
Supervisor: Black, Gary Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: C700 Molecular Biology, Biophysics and Biochemistry ; F100 Chemistry