Dr. Anthony Wilkinson
University of York

Structural studies of gankyrins

Minority groups suffer disproportionately from cancer, and disparities exist in both mortality and incidence rates. This is a project designed to characterize Gankyrin, a protein overexpressed in certain types of cancer cells.

Gankyrin is a protein which is overexpressed in certain types of cancer cells. It induces anchorage independent cell growth and tumour formation in certain mammalian cell cultures. The protein consists of six ankyrin repeat motifs. The ankyrin repeat is one of most common protein motifs. It consists of an ~33 residue sequence which in different proteins is repeated as few as two, and as many as 20 or more, times. The ankyrin repeat domains appear to be important in mediating protein-protein interactions. Our aim in the current project is to determine the structure of gankyrin by X-ray crystallography. We have E. coli clones which direct high level expression of recombinant protein. The first step will be to purify the protein by column chromatography methods and determine its subunit structure by analytical ultracentrifugation. The main aim is to grow crystals of gankyrin suitable for X-ray analysis. Should crystals appear we will attempt to solve their structure using diffraction methods.

Methods used: Growth of bacterial cultures, protein purification by column chromatography, gel-electrophoresis, analytical centrifugation, crystallisation.

Background of Student: The student should have experience in basic chemistry and biochemistry. Some knowledge of molecular biology would be an advantage.

References
1 & 2 are specific to this project 3 & 4 indicate the nature of the work in our lab.
1. Higashitsuji H. et al. (2000) Reduced stability of retinoblastoma protein by gankyrin, an oncogenic ankyrin repeat protein overexpressed in hepatomas. Nature Medicine 6, 96-99.
2. Sedgwick, S. G. and Smerdon, S. J. (1999) The ankyrin repeat: a diversity of interactions on a common structural framework. Trends Biochem Sci. 24, 311-316.
3. Lewis, R. J., Brannigan, J. A., Muchova, K., Barak, I. & Wilkinson, A. J. Phosphorylated aspartate in the crystal structure of a response regulator protein. J. Mol. Biol. 294 9-15 (1999).
4. Tyrrell, R. Verschueren, K. H. G., Dodson, E. J., Murshudov, G. N., Addy, C. & Wilkinson, A. J. The structure of the cofactor binding fragment of the LysR family member, CysB: a familiar fold with a surprising subunit arrangement. Structure 5, 1017-1032, (1997).