Dubin Research Group
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Our experimental tools vary from very simple ones (turbidimetry), to more complex methods (light scattering, capillary electrophoresis, rheology, and various microscopies). To ensure reproducible results, we focus on equilibrium systems. One of our interests is the unique dense, viscous liquid phase "coacervates" that form spontaneously from polyelectrolytes with oppositely charged micelles or proteins. Polyelectrolyte-enzyme coacervates function as microreactors because the protein retains its native state and diffuses freely in the dense fluid coacervate droplets. The surprising combination of high viscosity and fast diffusion arises from mesophase separation at the 300 nm length scale in these fluids. Polyelectrolyte-micelle coacervates also display unusual properties, phase separating by either heating or stress, a phenomenon known as "shear-banding".

Biologically significant protein binding occurs with a group of polyelectrolytes known as glycosaminoglycans (GAGs). These mammalian polysaccharides are the most highly charged macromolecules in animals. Although they play a role in the action of many signaling proteins responsible for tissue regeneration, angiogenesis and cell differentiation, structure-property relations for GAGs are unknown. Unlike proteins and nucleic acids, they are never homogeneous and therefore never "pure", so their characterization presents a huge challenge to classical biochemistry. We approach this problem with the model GAG-protein system of heparin-antithrombin, applying electrophoretic methods coupled with mass spectrometry and protein modeling

Department of Chemistry