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Andrea Cochran Senior Scientist: Protein Engineering |
"Projects in my lab involve diverse approaches to understanding protein function with the organizing theme of novel target or lead discovery in areas relevant to cancer. Because of the basic research aspect of many of the questions we have studied, critical contributions have been made by students (summer interns, co-op students, graduate students and postdocs) and visiting scientists. People who have come to my lab have trained in fields ranging from chemistry and chemical engineering to molecular biology.
Many interesting potential targets are protein-protein interactions. However, these are not considered traditionally "druggable" and often do not yield useful 'hits' in high-throughput screens. Past projects have therefore explored minimal requirements for protein-protein and protein-peptide recognition to better understand which targets may be tractable1, 2. Work in this area led us to study individual residue contributions to strand-strand recognition in -sheet proteins. These studies initially involved structural stability assays in peptides, leading to the design of a family of very small and stably folded β-hairpins (tryptophan zippers)3. To extend our work to larger proteins, we developed a quantitative phage display method to probe cross-strand residue pairing in β-sheets4, 5, (and in preparation).
More recently, the lab has been focused on the biochemistry and cellular function of mitotic protein kinases. We have probed activation mechanisms and cellular function by site-directed mutagenesis and applied phage display and truncation mutagenesis to define structurally important regions of reported binding partners. In a recent example, we have determined the structure of Survivin in complex with its key interactor in the chromosomal passenger complex6. Finally, we have employed proteomic techniques (affinity purification/mass spectrometry and yeast two-hybrid methods) to discover new binding partners and pathways. Future work will involve supporting these data with functional studies (localization, si/shRNA, mutagenesis, etc.). We are also starting projects in the area of epigenetic modifications.
1. Cochran, A. G. Antagonists of protein-protein interactions. Chem. Biol. 7, R85-R94 (2000).
2. Kayagaki, N.; et al. BAFF/BLyS receptor 3 binds the B cell survival factor BAFF ligand through a discrete surface loop and promotes processing of NF- ĸB2. Immunity 17, 515-524 (2002).
3. Cochran, A. G., Skelton, N. J., Starovasnik, M. A. Tryptophan zippers: stable, monomeric β-hairpins. Proc. Natl. Acad. Sci. USA 98, 5578-5583 (2001).
4. Distefano, M. D., Zhong, A., Cochran, A. G. J. Mol. Biol. 322, 179-188 (2002).
5. Kotz, J. D.; Bond, C. J.; Cochran, A. G. Phage display as a tool for quantifying protein stability determinants. Eur. J. Biochem. 271, 1623-1629 (2004).
6. Bourhis, E., Hymowitz, S. G., Cochran, A.G. The mitotic regulator Survivin binds as a monomer to its functional interactor Borealin. J. Biol. Chem. 282, 35018-35023 (2007).