This project has established that glycosylation is important for the normal, vegetative growth of <i>S. coelicolor</i>. Three genes SCO3154/<i>pmt, </i>SCO1423/<i>ppm1</i> and a putative SCO1014/<i>ppm2</i> 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 C<sub>45</sub> polyprenol phosphate mannose (Ppm) in <i>S. coelicolor.</i> In collaboration with researchers at Imperial College, London, we have characterised the endogenous polyprenol in <i>S. coelicolor,</i> shown that it consists of nine polyprenol units (C<sub>45</sub>) and provided evidence for the transfer of mannose from GDP-mannose to C<sub>45</sub> polyprenol phosphate. The transfer of mannose to polyprenol phosphates can be inhibited by the addition of amphomycin. The <i>pmt</i> mutant has been shown to contain C<sub>45</sub>-Ppm which implies that the role of Pmt is further down the glycosylation pathway. Glycosylation mutants in <i>ppm1, ppm2</i> and <i>pmt</i> were hypersensitive to rifampicin and cell wall acting drugs, bacitracin and tunicamycin. The <i>ppm1</i> and <i>ppm2</i> mutants were hypersensitive to vancomycin. The MIC of vancomycin for a putative <i>ppm2</i> mutant was between 10-20 μg ml<sup>-1</sup> whereas the WT was resistant to vancomycin at >200 μg ml<sup>-1</sup>. Phage resistance and small colony phenotype can be complemented; antibiotic sensitivities were partially complemented.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:446244 |
| Date | January 2008 |
| Creators | Varghese, Anpu Susan |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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