(753e) Monitoring Adsorption and Aggregation of an Intrinsically Disordered Protein at Solid Substrates

Authors: 
Gamblin, T. C., University of Kansas
Dhar, P., University of Kansas

Protein adsorption and aggregation at solid substrates, while a common phenomenon in both nature and during processing, is not well understood. Adsorption and aggregation of intrinsically disordered proteins at surfaces, is even less explored. In this talk, we will discuss our recent findings on the adsorption and aggregation of an intrinsically disordered protein at different solid surfaces. Using a combination of Quartz Crystal Microbalance with Dissipation, fluorescence microscopy and atomic force microscopy, we monitor the adsorption of wild type and mutant Microtubulue binding protein, Tau, to gold, silicon dioxide and polystyrene surfaces.  Our results indicate that while the adsorption of different proteins to the solid surfaces is concentration dependent, and reaches a saturation value, WT Tau shows increased adsorption and binding to all three surfaces when compared with an assembly incompetent mutant, suggesting that adsorption and binding are also related to aggregation potential. The binding to gold is found to be higher than SiO2 or polystyrene, suggesting that electrostatics plays a role in this process. We also find evidence of oligomer formation, using antibodies that bind specifically to oligomers. Since Tau protein is implicated in several neurodegenerative diseases, our results are also expected to provide more understanding of surface or interface induced protein aggregation in neurodegenerative diseases.
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