CHED 910 |
| The ligand-binding domain (LBD) of the estrogen receptor protein can be expressed as a folded peptide covalently attached to maltose binding protein. During purification, the 70kDA fusion protein is cleaved, releasing the 30kDa LBD. Both the fusion protein and LBD form non-covalently associated dimers in solution; the two interacting polypeptides exchange partners with a defined half-life. Studies have suggested that ligand binding effects the dimer exchange half-life. Because ligands have limited solubility in water, they are pre-dissolved in organic solvents. Full characterization of the ligand effect requires understanding the effect of solvents on the protein. Dimer exchange kinetics were measured using HPLC following pre-incubation with organic solvent. The half-life of wild-type protein was two hours. Low concentrations (0.1 to 0.5% by volume) of small mono-functional alcohols reduced the half-life in a concentration-dependant manner. The half-life decrease was positively correlated with the alcohol boiling point, suggesting that the effect is mediated by non-polar interactions with the protein. Changes in the dimer exchange half-life imply perturbations affecting the dimer interface; characterizing these effects may improve understanding of the estrogen receptor protein. The low concentrations of alcohols used suggest physiological significance to these studies. |
|
Undergraduate Research Poster Session: Biochemistry
2:00 PM-4:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Chemical Education |