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Title: Investigation of Streptomyces coelicolor A3(2) glycosylation mutants
Author: Varghese, Anpu Susan
ISNI:       0000 0001 3542 7993
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2008
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This project has established that glycosylation is important for the normal, vegetative growth of S. coelicolor.  Three genes SCO3154/pmt, SCO1423/ppm1 and a putative SCO1014/ppm2 have been identified to be part of the pathway that carries out glycosylation in general, as well as for glycosylation of a phage (πC31cδ25) receptor. The three genes encode protein mannosyltransferase, Pmt and polyprenol phosphate mannose synthases, Ppm1, and Ppm2.  Of the three, Ppm2 was previously uncharacterised.  Radiolabelling experiments have shown that Ppm1 and Ppm2 are essential for the synthesis of C45 polyprenol phosphate mannose (Ppm) in S. coelicolor. In collaboration with researchers at Imperial College, London, we have characterised the endogenous polyprenol in S. coelicolor, shown that it consists of nine polyprenol units (C45) and provided evidence for the transfer of mannose from GDP-mannose to C45 polyprenol phosphate.  The transfer of mannose to polyprenol phosphates can be inhibited by the addition of amphomycin.  The pmt mutant has been shown to contain C45-Ppm which implies that the role of Pmt is further down the glycosylation pathway.  Glycosylation mutants in ppm1, ppm2 and pmt were hypersensitive to rifampicin and cell wall acting drugs, bacitracin and tunicamycin.  The ppm1 and ppm2 mutants were hypersensitive to vancomycin.  The MIC of vancomycin for a putative ppm2 mutant was between 10-20 μg ml-1 whereas the WT was resistant to vancomycin at >200 μg ml-1.  Phage resistance and small colony phenotype can be complemented; antibiotic sensitivities were partially complemented.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available