Dimethylsulphoniopropionate (DMSP) is the most abundant sulphur molecule in the oceans. Catabolism of DMSP by marine organisms is important both for the global movement of sulphur and as a carbon and sulphur source for microbial life. The molecular basis of DMSP catabolism had been revealed by the discovery of a DMSP demethylase and six different lyases in marine bacteria. However, at the start of this study in 2009 no eukaryotic DMSP lyase had been isolated, purified or characterized from axenic cultures, and there was little information on the enzymology of any of the bacterial DMSP lyase enzymes. The work presented in this thesis identifies the requirement of the three bacterial cupin DMSP lyases DddL, DddQ and DddW for metal cofactors, and also establishes the enzymology and biochemistry of these cupin-containing DMSP lyases. The presence of a typical DMSP lyase in the coccolithophore Emiliania huxleyi RCC1217 is also demonstrated for the first time from bacteria-free cultures by application of previously successful techniques used in the purification of bacterial ddd genes. Combined these findings provide new insights into the mechanisms of cleavage of DMSP by bacteria and phytoplankton and expand our understanding of the enzyme diversity involved in this process.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:687909 |
| Date | January 2015 |
| Creators | Newton-Payne, Simone |
| Publisher | University of East Anglia |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://ueaeprints.uea.ac.uk/59619/ |
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