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Title: Genetic and biochemical studies of the biosynthesis of glycopeptide and aminoglycoside antibiotics
Author: Fan, Q.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2009
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My project explored the biosynthesis of teicoplanin and neomycin as representatives of glycopeptides and aminoglycosides respectively, with a focus on the characterisation of the biosynthetic enzymes and the development of methods for targeted gene disruption in the producer strains. Both Actinoplanes teichomyceticus ATCC 31121, the teicoplanin producer, and Streptomyces fradiae NCIMB 8233, the neomycin producer, were successfully conjugated. This allowed in vivo study of specific enzymes involved in the biosynthetic pathway. Several aspects of teicoplanin biosynthesis were studied: first, the timing and the mechanism of β-hydroxylation of the tyrosine monomer in the backbone of teicoplanin; secondly, the role of the uncharacterised X-domain in the last module of NRPS; and finally, the enzyme responsible for deacetylation of the N-acetyl-glucosaminyl moiety attached to the fourth amino acid of the heptapeptide. Late-stage neomycin biosynthesis, including steps of glycosylation, deacetylation and O-ribosylation, was studied using both in vivo and in vitro approaches. Two glycosyltransferases and one deacetylase were characterised through heterologous expression in Escherichia coli and gene inactivation in S. fradiae. Feeding pathway intermediates to the mutants revealed the possibility of the existence of an inducible second copy of at least some of the biosynthesic enzymes.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available