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Postgraduate Training:
Cancer Medicinal Chemistry:
4 year programme funded by CRUK
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Chemical Biology
The Hulme group is interested in the design and synthesis of small molecule probes to investigate the interactions of biomolecules both in vivo and in vitro.
Anisomycin Activation of SAPK Pathways
Since its discovery in 1954, anisomycin has been found to generate many interesting biological responses including; anti-fungal activity, protein synthesis inhibition, and anti-tumour activity in the nM region. More recently anisomycin has been used as a chemical stimulant of the stress activated protein kinase (SAPK) pathways and we have investigated the structure activity relationship (SAR) of anisomycin in this role (Org. Biomol. Chem., 2004). Although the downstream effects are known (strong activation of both p38 and JNK pathways), the precise cellular target(s) of anisomycin have not yet been identified. The SAPK pathways play an important role in a number of diseases including Alzheimer's, and cancer and hence an understanding of their regulation is crucial. We have designed fluorescent (Org. Biomol. Chem., 2007) and biotinylated molecular probes based on anisomycin using a "click" chemistry approach (Bioconj. Chem., 2007). These probes retain their activity, as shown in SAPK pathway immunoblot assays, and we are currently using them to identify the intracellular target of this intruiging natural product.
Conformational Analysis of Glycosaminoglycans
Glycosaminoglycans (GAGs) are linear polysaccharides found on most animal cell surfaces, on many intracellular membranes, and also in extra-cellular matrices. They are composed of alternating hexosamine and uronic acid residues which are highly sulfated, and they have very heterogeneous structures due to variations in oligosaccharide content and degree of sulfation. GAGs interact with protein targets through a series of electrostatic interactions and are thought to play important roles in a number of signalling pathways. However, very little is known about the solution conformation of these molecules. We have recently reported a DMT-MM mediated coupling reaction for the selective introduction of labelling groups to the non-reducing end of a GAG oligosaccharide (Chem. Commun., 2007). This opens up new opportunities for studying the solution conformation and protein-GAG interactions of this class of biomolecule using techniques such as time-resolved Fluorescence Resonance Energy Transfer (tr-FRET) and NMR footprinting. We are currently pursuing these approaches with our collaborators Dr. Anita Jones and Dr. Dusan Uhrín.
A "Click" Approach to Detecting Cu(I) in Cells
Copper is an essential trace metal found in all living organisms in the oxidised Cu(II) and reduced Cu(I) states. However, the reduced state, Cu(I), is highly toxic to cells and hence is exclusively found complexed to proteins or other pooling agents such as the tripeptide glutathione (GSH). Indeed the concentration of free Cu(I) ions in a cell has been estimated at 10-15 M, or roughly one free ion per cell! Disrupted copper homeostasis can be very damaging and has been implicated in diseases such as Wilson’s disease, Alzheimer’s disease, cystic fibrosis and Parkinson’s disease. Designing a sensor for Cu(I) which is based on the complexation of free Cu(I) is not an appropriate strategy due to the lack of free ions; instead we have designed a sensor which is based upon the Cu(I)-catalysed formation of the sensor. Briging together an antenna and a lanthanide-DOTA complex via a Cu(I)-catalysed Huisgen 1,3-dipolar cycloaddition reaction (or "click" reaction) allows us to form a luminescent sensor (J. Am. Chem. Soc., 2006). The advantages of our approach have been highlighted in a review article by Prof. Otto Wolfbeis in Angewandte Chemie. We believe that our lanthanide "click" component has many other potential applications; some of which we are currently investigating.
