Natural product macrocyclic architectures effectively target the large contact areas of protein-protein interactions (PPIs) through a complex series of hydrophobic interactions. A number of molecules target interfere with microtubule assembly and dynamics, some of which used in cancer treatment. The synthetically-challenging family of cytotoxic natural products, the disorazoles, possess nM to pM cytotoxic and anti-tubulin properties and to date pharmaceutical interest has focused on their potential for the treatment drug-resistant solid tumours. Very recent crystallographic studies suggest that they bind at the maytansine binding site on β-tubulin, which is exposed at the plus end of microtubules .
Recently the Hulme group demonstrated the first example of a new synthetic strategy to generate a disorazole precursor . This proposed project will take this research in a new direction – exploring the use of disorazole-inspired natural product scaffolds as tools to dissect the role of the cytoskeleton in collaboration with Dr Julie Welburn (Edinburgh) .
The student will optimize the disorazole compounds chemically using a modular synthetic approach and molecular modelling, unique to the Hulme lab. The student will explore disorazole analogues computationally (Autodock, Flare etc) using the recently reported crystal structure (PDB: 6FJM) to determine the optimum geometry of the macrocyclic scaffold ring and to explore binding at a maytansine sub-site. Using knowledge gained from current studies, disorazole-like scaffolds will be synthesised which can direct the selected substituents into this orthogonal binding pocket. The Hulme group strategy allows rapid construction of scaffold rings, allowing effective realisation of this approach for the first time.
The student will determine the biological activity of the synthesized compounds. They will first characterise the compounds biophysically on purified tubulin and test its activity on microtubule dynamics and assembly in vitro. This will give them opportunity to learn protein purification and isolation, in vitro reconstitution approaches using microtubules, single molecule microscopy techniques to image microtubules and fluorescently labelled drugs. The student will then extend their studies to cell culture models to examine the effect of their synthesized compounds on microtubule organization in cells and in particular examine the effects of the compounds on the mitotic spindle and how it interferes with cell division. The student will also develop these compounds that target the maytansine sub-site as plus end markers in systems which are difficult to modify genetically or transfect.
This project enables a motivated Ph.D. student to apply chemistry, cell biology, biochemistry and in vitro reconstitution assays to investigate the molecular properties of microtubules and develop new tools for study of the cytoskeleton. These results will have strong implications for our understanding of the synthesis of macrocyclic drugs, cytoskeleton biology and chromosome segregation.
The PhD student will be co-supervised by Prof Alison Hulme (School of Chemistry) and Dr Julie Welburn (School of Biology).
Lab websites: http://www.chem.ed.ac.uk/staff/academic-staff/professor-alison-hulme http://welburn.bio.ed.ac.uk/
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If you would like us to consider you for one of our scholarships you must apply by 5 January 2020 at the latest.
 A fluorescence anisotropy assay to discover and characterize ligands targeting the maytansine site of tubulin: G. Menchon, A. E. Prota, D. Lucena-Agell, P. Bucher, R. Jansen, H. Irschik, R. Müller, I. Paterson, J. F. Díaz, K.-H. Altmann, M. O. Steinmetz, Nature Commun., 2018, 9, 2106.
 Self-assembly of disorazole C1 through a one-pot alkyne metathesis homodimerization strategy: K. J. Ralston, H. C. Ramstadius, H. S. Niblock, R. C. Brewster, A. N. Hulme, Angew. Chem. Int. Ed. 2015, 54, 7086-7090.
 Microtubule end tethering of a processive kinesin-8 motor Kif18b is required for spindle positioning: T. McHugh, A. A. Gluszek, J. P. I. Welburn, 2018, 217, 2403-2416.