No description available.

No description available.

No description available.

This thesis compares methods of producing protein for structural analysis by NMR spectroscopy and describes the structural characterisation of the N-terminal CP-module of membrane cofactor protein (MCP-1). CP-modules are autonomously folding domains composed of approximately sixty amino acids. They are defined by a consensus sequence including four cysteines, and have been identified in over forty different proteins. The proteins discussed in this thesis, MCP and factor H, are members of the regulators of complement activation family. Each comprises a contiguous array of CP-modules which serve as the binding sites for complement components and various other ligands. The structures of CP-modules have been determined previously by NMR and X-ray crystallography. Whilst individual modules are structurally similar, the nature of the interface between modules is highly variable. The high-resolution structure determination of MCP-1 forms part of an on-going study to determine the structure of the extracellular portion of MCP. MCP-1 is of particular interest as it comprises part of the measles virus receptor. It is anticipated that understanding the structural characteristics of this module in solution may assist in determining the nature of the interaction with the virus. Synthetic and recombinant methods have been assessed for the production of CP-modules in sufficient yield and purity for structure determination by NMR. Two CP-modules, MCP-1 and the fifteenth module of factor H (fH~15), were synthesised using standard Fmoc methodology. fH~15 was used as a model since the 3D-solution structure of this stable and soluble module has been determined by NMR. The purification and renaturation strategy utilised a number of chromatographic techniques and was monitored by mass spectrometry and NMR. However, it was not possible to purify the synthetic modules to homogeneity in sufficient yield for structural analysis.

This thesis describes the development of the various methods available for the synthesis of deoxyoligoribonucleotides. The use of the 2,2-bis (4-nitro-phenyl)ethyl group was investigated, mainly as a 5'-hydroxyl protecting group on 2'-deoxyribonucleotides, but also as a base protecting group for the O4-function of thymidinc and the Nc-exocyclic amine of adenosine. The deprotection conditions required for the removal of this group and its subsequent use in the synthesis of 2'-deoxyribonucleotides utilising phosphoramidite methodology arc described. An investigation, by 81P n.m.r., of the coupling and oxidation steps of the synthesis of DNA is included as well as a brief study of the potential use of zinc iodide as an accelerating agent in the coupling of nuclcotidcs by the phosphotriester method of synthesis.

This thesis documents the development of serine derived aldehyde 73 and its application to natural product synthesis. (Fig. 9978A) Highly efficient syntheses of the biologically important natural products DAB1 35 and nectrisine 36 from aldehyde 73 are discussed. The synthesis of these molecules made use of highly efficient asymmetric boron mediated <i>syn</i> aldol reaction to generate a common intermediate, lactam 114. (Fig. 9978B) A alternate synthesis of lactam 114, making use of the Sharpless asymmetric dihydroxylation reaction is also discussed, along with an extension of the aldol reaction methodology which allowed the development of syntheses directed toward the C₄Me analogue of 35 and the C₃Me analogue of 36. Finally, the utility of aldehyde 73 towards the synthesis of the potential hydantocidin analogues 176 and 181 and the lactacystin analogue 183 was investigated (Fig. 9978C).

No description available.

No description available.

It is possible for some chemicals to achieve an effect within a system other than that of the intended/desired result for which they were employed. One such side effect can be the perturbation of an organism’s endocrine system. Chemicals capable of this are collectively known as “endocrine disrupting chemicals” (EDCs). The presence of these EDCs in the environment has the potential to cause adverse effects in wildlife and humans. This investigation focuses on two EDCs, nonylphenol (NP) and nonylphenol polyethoxylates (NPEO_x), and their occurrence in various environmental matrices. NPEO_x is a surfactant used in a variety of applications including detergents and pesticides. NP is used in the production of certain types of plastic and is also found during the biodegradation of NPEO_x. Methods for the extraction (e.g. liquid/liquid, solid phase, Soxhtherm and Accelerated Solvent Extraction (ASE)) and analysis (i.e. GC-MS and LC-MS) of these chemicals from waste water treatment works (WWTW) waters, industrial effluents, river waters, sludges and sediments were developed and applied. A study of six WWTW was conducted to investigate concentrations of NP (1.1-29.3 mg/l) and NPEO_x (1.6-28.4 mg/l) in effluents within each works. It was found that several, but not all, WWTW effluents contained detectable concentrations. An investigation of the bottom sediments of two contrasting freshwater lochs, Tay and Leven, showed that neither NP nor NPEO_x was detectable in bottom sediments from Loch Tay, whereas Loch Leven bottom sediments revealed detectable concentrations of NP (8-631 mg/kg) and NPEO_x (87-925 mg/kg). Other matrices, including single-amended soils (239-586 mg/kg NP and 123-343 mg/kg NPEO_x), WWTW sludges (86-3843 mg/kg NP and <0.45-<10.8 mg/kg NPEO_x), and river waters (1.1-5.4 mg/l NP and 0.6-1.6 mg/l NPEO_x, also had detectable concentrations in some of the samples. Improvement of NP and NPEO_x removal processes by the water industry, during water purification, is needed as contamination by waste water effluents introduces NP into the fresh water environment at concentrations above the recommended safe level of 1.0 mg/l (Environmental Agency for England and Wales). No recommended limits have been set for NPEO_x at this juncture.

A novel linker for the solid phase synthesis of peptide amides is described. This linker based on 2-alkoxydibenzocycloheptadiene enables release of the peptide derivative under very mild conditions and is compatible with base labile N-alpha protecting groups. The efficacy of this linker in generating c-terminal peptide amides has been demonstrated in the synthesis of the natural products, little gastrin, big gastrin, substance P and bombesin. Modification of the linker allows peptide hydrazides to be prepared. The use of the linker in producing unprotected peptide hydrazides has been exemplified in the synthesis of the ubiquitin fragments (43-47)NHNH2 and(67-76)NHNH2. Use of the linker for the synthesis of fully protected peptide hydrazides requires further development. Initial experiments indicate that the linker, when appropriately substituted, may also be useful for the solid phase synthesis of fully protected peptide free acids to be used in fragment condensation.