Synthetic and analytical studies of phytochelations, the metal(loid)-binding peptides of terrestrial plants
This thesis describes research based around phytochelatins (PCs), plant peptides synthesised during the influx of metal(loid)s such as arsenic. Development of synthetic strategies for production of PCs and a bromine-based thiol tag were pursued. The role of PCs in the arsenic translocation system...
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ndltd-bl.uk-oai-ethos.bl.uk-5404372015-03-20T05:24:47ZSynthetic and analytical studies of phytochelations, the metal(loid)-binding peptides of terrestrial plantsWood, Barry Alan2011This thesis describes research based around phytochelatins (PCs), plant peptides synthesised during the influx of metal(loid)s such as arsenic. Development of synthetic strategies for production of PCs and a bromine-based thiol tag were pursued. The role of PCs in the arsenic translocation system in plants was monitored firstly by statistical analysis, then by monitoring arsenic translocation of <i>L-</i>BSO-poisoned and mutant plants. Whilst protected PC<sub>2</sub> was synthesised in good yield, subsequent isolation of deprotected PC<sub>2</sub> was not achieved via SEC or RP chromatography. Statistical analysis showed that differential transport of iAs(V) and DMA(V) <i>in planta </i>between two plant groups was not due to PC/As(III)-PC speciation difference, but this was far from conclusive. Plants exposed to iAs(V) and the <i>PC synthase </i>inhibitor <i>L</i>-BSO showed increased arsenic translocation with decreasing As(III)-PC levels, but the trend was not statistically significant. Analysis of <i>Arabidopsis thaliana </i>mutants with differing PC levels confirmed that arsenic translocation increased with reduced PC and As(III)-PC complex levels. HR-ICP-MS quantified unbound PC species on <i>m/z</i> 32 (S<sup>+</sup>), whilst HR-ESI-MS identified the (GS)<sub>3</sub>-As(III) complex for the first time <i>in vivo</i>. Whilst significant levels of iAs(III) and PC<sub>2</sub> exist within seaweeds, no As(III)-PC complex formation was observed. This indicates a transient role, if any, for PCs during the <i>in vivo </i>detoxification of arsenic within seaweeds. The development of a thiol tag based upon a polybrominated-pyrrole moiety was unsuccessful, owing to the greater-than-anticipated complexity of the chemistry exhibited by pyrrole.547.7University of Aberdeenhttp://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540437Electronic Thesis or Dissertation |
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547.7 Wood, Barry Alan Synthetic and analytical studies of phytochelations, the metal(loid)-binding peptides of terrestrial plants |
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This thesis describes research based around phytochelatins (PCs), plant peptides synthesised during the influx of metal(loid)s such as arsenic. Development of synthetic strategies for production of PCs and a bromine-based thiol tag were pursued. The role of PCs in the arsenic translocation system in plants was monitored firstly by statistical analysis, then by monitoring arsenic translocation of <i>L-</i>BSO-poisoned and mutant plants. Whilst protected PC<sub>2</sub> was synthesised in good yield, subsequent isolation of deprotected PC<sub>2</sub> was not achieved via SEC or RP chromatography. Statistical analysis showed that differential transport of iAs(V) and DMA(V) <i>in planta </i>between two plant groups was not due to PC/As(III)-PC speciation difference, but this was far from conclusive. Plants exposed to iAs(V) and the <i>PC synthase </i>inhibitor <i>L</i>-BSO showed increased arsenic translocation with decreasing As(III)-PC levels, but the trend was not statistically significant. Analysis of <i>Arabidopsis thaliana </i>mutants with differing PC levels confirmed that arsenic translocation increased with reduced PC and As(III)-PC complex levels. HR-ICP-MS quantified unbound PC species on <i>m/z</i> 32 (S<sup>+</sup>), whilst HR-ESI-MS identified the (GS)<sub>3</sub>-As(III) complex for the first time <i>in vivo</i>. Whilst significant levels of iAs(III) and PC<sub>2</sub> exist within seaweeds, no As(III)-PC complex formation was observed. This indicates a transient role, if any, for PCs during the <i>in vivo </i>detoxification of arsenic within seaweeds. The development of a thiol tag based upon a polybrominated-pyrrole moiety was unsuccessful, owing to the greater-than-anticipated complexity of the chemistry exhibited by pyrrole. |
author |
Wood, Barry Alan |
author_facet |
Wood, Barry Alan |
author_sort |
Wood, Barry Alan |
title |
Synthetic and analytical studies of phytochelations, the metal(loid)-binding peptides of terrestrial plants |
title_short |
Synthetic and analytical studies of phytochelations, the metal(loid)-binding peptides of terrestrial plants |
title_full |
Synthetic and analytical studies of phytochelations, the metal(loid)-binding peptides of terrestrial plants |
title_fullStr |
Synthetic and analytical studies of phytochelations, the metal(loid)-binding peptides of terrestrial plants |
title_full_unstemmed |
Synthetic and analytical studies of phytochelations, the metal(loid)-binding peptides of terrestrial plants |
title_sort |
synthetic and analytical studies of phytochelations, the metal(loid)-binding peptides of terrestrial plants |
publisher |
University of Aberdeen |
publishDate |
2011 |
url |
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540437 |
work_keys_str_mv |
AT woodbarryalan syntheticandanalyticalstudiesofphytochelationsthemetalloidbindingpeptidesofterrestrialplants |
_version_ |
1716791069617684480 |