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Abstract
Enzymes are natural catalysts that orchestrate metabolic processes in live cells. Because of their high efficiency, selectivity, and biocompatibility, the applications of these catalysts were extended to many industrial and biomedical technologies. The properties of enzymes can be described through stability and catalytic activity. This dissertation aims to develop enzyme complexes with polymer and DNA scaffolds to improve thermal stability and catalytic activity of protein molecules. Elevated temperatures are widely used for many applications to increase process rates and decrease bacterial contaminations. However, most mesophilic enzymes denature at temperatures above 50−60 °C due to the unfolding of protein molecules. A “grafting through” conjugation strategy was designed to improve lysozyme thermal stability by the synthesis of a synthetic polymer−enzyme hybrid, and the conjugates have extended lysozyme half-life up to 9 times at 90°C. The mechanism of thermal stabilization was investigated with the addition of polyethylene glycol (PEG) crowders. The catalytic activity is another significant property of enzymes, which describes the efficiency in degrading substrates. Multi-enzyme complexes usually delivered a synergistic effect with higher catalytic activity compared to single molecules. Cellulosomes are bacterial protein complexes that bind and efficiently degrade lignocellulosic substrates with synergy effects of different enzymes. Creation of artificial cellulosomes based on DNA scaffolds was developed to illustrate the synergy effect of enzymatic complexes and discover impacts of sequencing and spatial arrangement of enzymes in the complex.