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theses

This work developed an experimentally verified computational protocol (called ZPRED) for modeling the zeta potential of molecules (e.g. proteins or drugs) from their structure with the long-term goal of being used as a design tool for predicting the onset of molecular self-assembly. The zeta potential (ζ) is the effective charge energy of a solvated molecule and is commonly used to assess how well separated molecules remain in solution (e.g. in pharmaceuticals, medical diagnostics, cosmetics, etc.). The ζ exists at a position away from the molecular surface, where ions and water no longer adhere to the protein, called the slip plane position (XSP). However, the information gap is the XSP is not generally defined and can vary based on solution conditions (ionic strength, pH, and temperature) as well as flow at the protein-solvent interface. Thus, the objective of this work aims to relate the XSP of select, compact globular proteins to their solution conditions and attempts to extend the relation to general fibrillar proteins using a collagen-like triple helix as a model system. Completing this objective tested the central hypothesis: the XSP coincides with the solvation edge defined by the Stokes-Einstein hydrodynamic radius (Rh), and thus the two should hold the same dependence on solution conditions. The rationale is since diffusing globular proteins hold similar translational motion during electrophoresis; hydration should be equivalent when solution conditions are held constant with any deviation representing the difference in flow perturbations at the protein-solvent interface. This work was accomplished through variation in each solution condition ensuring ZPRED to be accurate for any general aqueous electrolyte solution. Experimental light scattering methods indicated coincidence of the XSP and Stokes-Einstein hydrodynamic radius for a number of proteins in a wide range of solution conditions

ETD_9036

Ph.D.

Includes bibliographical references

by Daniel Robert Grisham

doi:10.7282/t3-17sz-j786

ETD doctoral

The author owns the copyright to this work.