Date of Completion

1-23-2013

Embargo Period

7-22-2013

Keywords

Chemical modification, Enzymes, Stability, Glucose oxidase, Hemoglobin, Poly(acrylic acid), Isothermal titration calorimetry, Energy transfer, DNA, Bovine serum albumin

Major Advisor

Dr. Challa V. Kumar

Associate Advisor

Dr. Rajeswari M. Kasi

Associate Advisor

Dr. Xudong Yao

Associate Advisor

Dr. Fatma Selampinar

Associate Advisor

Dr. Yao Lin

Field of Study

Chemistry

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

The goal of this thesis was to explore how to improve the functionality of proteins as biomaterials by chemical modification of the surface of the protein. In order to achieve this goal protein surfaces were decorated with small amine molecules and large synthetic polymers. The introduced functionality by the facile modification, allowed the protein to behave as a successful bio catalysts, bio sensor and a useful scaffolding platform.

Thorough characterization was performed using various biochemical, bioanalytical biophysical methods to evaluate the structural integrity, enzymatic activity , thermodynamic and kinetic stability of chemically modified proteins/enzymes. Improved stability and reversible thermal denaturation were key stand out properties observed with chemical modification.

The study was further expanded to understand the effect of modification for the interaction between chemically modified protein and macromolecules. As a model system triethylenetetramine modified hemoglobin and polyacrylic acid were used to investigate the charge dependency on thermodynamics of protein/polymer interaction. A collaborative research project between Kasi and Kumar groups exploit the protein/polymer interaction towards a development of bio sensor to detect small molecules.

Furthermore we studied the chemically modified bovine serum albumin (BSA) as a scaffolding platform for construction of protein and DNA based artificial antenna complex to capture solar energy. Chemical modification allows BSA to reverse its negative charge and facilitate the binding to DNA. Donors and acceptor chromophores were loaded in DNA/BSA scaffold and functioned as an efficient and stable antenna complex. Thus, functionalities introduced to the protein by chemical modification have shown a major influence towards the application of proteins as successful functional biomaterials.

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