Synthesis of hybrid fluorous surfactants and their application as additives for protein renaturation
During the course of our studies with fluorous surfactants, it was discovered that fluorous hybrid detergents show promise as refolding reagents for denatured proteins. To begin to understand this phenomenon, preliminary refolding studies were performed on chemically and thermally denatured bovine carbonic anhydrase (CAB) using a series of hemifluorinated surfactants containing a sulfonate head group. Preliminary data shows that these surfactants provide good refolding yields at low as well as high concentrations of CAB compared to their hydrocarbon analogs. In contrast to traditional surfactants, we discovered that hybrid fluorous surfactants are most efficient at concentrations well below their critical micelle concentrations. This talk will present the synthesis and characterization of various hybrid fluorous surfactants and their utility in the renaturation of various structurally different proteins. The relationship between surfactant structure and efficiency in renaturation will also be discussed.
Free-Solution Comparison of DNA Hybridization using Isothermal Titration Calorimetry and Backscattering Interferometry
The characterization of biomolecular binding interactions is crucial to the understanding of biological processes and comparison of therapeutic efficacies. This study uses the novel technique of backscattering interferometry with an ITC benchmark to examine the impact of surface immobilization and the presence of a labeled probe on binding affinity. Specifically, the binding affinity of DNA hybridization with and without a fluorescent probe will be compared using both free-solution and surface-bound methodologies. The results from these experiments show a significant increase in the binding affinity for free-solution, label-free DNA hybridization compared to fluorescently labeled, surface-bound DNA hybridization. Additionally, the utility of backscattering interferometry will be compared to ITC as an analytical technique for studying various intermolecular interactions.
Solvation Controlled Luminescence of Sm(II) Complexes
Changes in solvation of samarium diiodide (SmI2) can significantly alter the interaction between a ligand and metal. Addition of the appropriate crown ether to SmI2 in acetonitrile not only stabilizes the ground state complex but also generates a highly luminescent complex. The advantage of direct excitation of lanthanide(II) complexes includes elimination of different deactivation pathways as well as the multi-step syntheses involved in preparing antenna ligands necessary for producing luminescent lanthanide(III) complexes. We demonstrate how controlling the coordination sphere of SmI2 through changes in solvation induces remarkable changes both in the ground and excited states. By providing a chelating ligand for SmI2 in a solvent incapable of displacing it significantly enhances the luminescent properties of Sm(II) by: 1.) encapsulating the metal through a strong metal-ligand interaction and 2) decreasing the frequency of solvent collision. This study led to the discovery of the longest reported excited-state lifetime for a Sm(II) complex in solution.