Research Areas of Interest

Targeting Protein-Protein Interactions

We have developed a method for enhancing the apparent molecular mass of small molecules by borrowing the bulk of cellular proteins. In this strategy, we synthesize a compound that binds to the desired target on one end and to the FK506-Binding Protein (FKBP) on the other. Thes chemical domains are non-overlapping, so the bifunctional molecule can bind both partners at the same time. For example, we have synthesized a compound that binds to the amyloid beta (Aβ) peptide, which is implicated in Alzheimer’s disease. Aβ self-associates into oligomers that are highly neurotoxic. Small molecule strategies to inhibit Aβ-Aβ interactions have been largely unsuccessful, partly due to the low mass and contact surface of the pharmacophores. To address this limitation, we generated bifunctional molecules that bind with high affinity to both Aβ and FKBP. The combination of the bifunctional drug and FKBP has a composite molecular weight of over 13,000 Da. The drug-protein complexes are potent inhibitors of Aβ aggregation (IC50 ~ 50 nM) and block Aβ neurotoxicity. More recently, we have also found that bifunctional molecules can be used to target HIV-1 protease, an important drug target for AIDS. Thus, this method may find widespread application in preventing protein-protein interactions where small molecules alone are insufficient.

Some Reading

Marinec, P. S., Lancia, J. K., Gestwicki, J. E. “Bifunctional molecules evade cytochrome P450 metabolism by forming protective complexes with FK506-binding protein” Mol. Biosystems. 2008, 4:571-578.

Gestwicki, J. E. and Marinec, P. S. “Chemical control over protein-protein interactions: beyond inhibitors” Combi. Chem. High Throughput Screen. 2007, 10(8):667-675.

Gestwicki, J. E.; Crabtree, G. R.; Graef, I. A. “Harnessing chaperones to generate small molecule inhibitors of amyloid β aggregation” Science, 2004, 306:865-869.

What Types of Methods Might You Learn/Use on this Project?

synthetic organic chemistry, NMR, LCMS, high-throughput screening, protein expression/purification, biochemical analysis of macromolecular interactions

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Chemical Probes for Molecular Chaperones

Molecular chaperones assist in the folding of newly synthesized polypeptides. If folding is not accomplished, then the chaperones help degrade the misfolded substrates. Thus, chaperones are crucial in the decision to fold or degrade a protein and they are central to maintaining cellular protein homeostasis. These functions are especially important in neurodegenerative disorders, such as Alzheimer’s disease, which are caused by the accumulation of misfolded proteins. In these diseases, a peptide undergoes abnormal protein-protein interactions that allow it to avoid chaperone-mediated degradation. We are using high throughput screening and molecular design to identify potent, chemical modulators of the chaperone system. In turn, we are using these compounds to ask questions about the relationship between chaperones and protein folding in neurodegenerative disease, cancer and bacterial pathogenesis. We believe that these novel chemical tools will allow us to ask increasingly sophisticated questions that haven’t been previously accessible.

Some Reading

Wisén, S., Androsavich, J., Evans, C. G., Chang, L. and Gestwicki, J. E. “Chemical modifiers of heat shock protein 70 (Hsp70) by sequential, microwave-accelerated reactions on solid phase” Bioorgan. Med. Chem. Lett. 2008, 18:60-65.

Chang, L., Bertelsen, E. B., Wisén, S., Larsen, E. M., Zuiderweg, E. R. P., Gestwicki, J. E. “High throughput screen for small molecules that modulate the ATPase activity of the molecular chaperone, DnaK” Anal. Biochem. 2008, 372:167-176.

Evans, C. G.; Wisén, S.; Gestwicki, J. E. “Heat shock proteins 70 and 90 inhibit early stages of amyloid beta aggregation in vitro” J. Biol. Chem. 2006, 281:33182-33191.

What Types of Methods Might You Learn/Use on this Project?

high-throughput screening, protein expression/purification, analysis of macromolecular interactions, structural biology, fluorescence microscopy, molecular modeling, cell-based assays