Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 113-126).

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Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 177-194).

Reliable design of artificial metalloenzymes (ArMs) to access transformations not observed in nature remains a long-standing and important challenge. We report that a monomeric streptavidin (mSav) Rh(III) ArM permits asymmetric synthesis of α,β-unsaturated-δ-lactams via a tandem C-H activation and [4+2] annulation reaction. These products are readily derivatized to enantioenriched piperidines, the most common N-heterocycle found in FDA approved pharmaceuticals. Embedding a Rh cyclopentadienyl (Cp*) catalyst in the active site of mSav results in improved stereocontrol and a seven-fold enhancement in reactivity relative to the isolated biotinylated Rh(III) cofactor. With the goal of using protein engineering to improve the activity of monomeric streptavidin (mSav) ArM complexed to Rh(III), we also report computational calculations that demonstrate the effects of modifying the secondary coordination sphere. These findings have allowed us to engineer a more active mutant G49A that provides up to 67 more TON compared to WT mSav ArM. Directed evolution techniques, when applied to ArMs, allows us to mimic the natural selection process and thereby dramatically increase the TON of the ArM. This technology has been used to develop an artificial aminobrominase with up to 2587 TON.

In this study, we used E. coli strain BL21 (DE3) to express the recombinant protein his-tag streptavidin. To find out the optimal production conditions, we studied on the culture conditions, medium composition, induction conditions and the timing of induction. In the purification processes we tried to find out the difference between hydrophobic column and affinity column. We also tested the effect of heat treatment on the crude extract to increase the recombinant protein yield. The results showed that when cultured in LB medium, the optimal culture conditions of recombinant protein expression are 37¢XC, pH 6.0 to 7.0, and the induction temperature is 37¢XC. The best induction time is at late log phase or the early stationary phase when OD600 values reached to the ranged of 1.1 to 1.8. The inducer, IPTG concentration is 0.1 mM, which can also replaced with 2 mM lactose. The best production medium is TB medium. When cultured in 5 liters fermentor with optimal culture and induction condition, the highest recombinant protein yield could be 81.1 mg /L. To improve the purification process, we used a affinity chromatography. The purified high homogeneous recombinant protein had a high biotin binding activity up to 14 U / mg, and the recovery yield could be as high as 97% in comparing with the hydrophobic column was only 51%. When we treated the crude extract with 75 ¢J for 10 min, the biotin binding activity was 14.1 U / mg, but the recovery rate decreased to 64 %.

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains ix, 115 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 103-105).

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 165-172).

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [66]-73).

A study to optimise an IgG based immunosensor is presented, that has been carried out by absorbing monolayers to a gold transducer surface at varying immersion times and temperatures. The theory and kinetics of monolayer adsorption are analysed and discussed. Existing mathematical models are reviewed and experimentally researched, to highlight gaps in knowledge that would facilitate high quality, cost effective immunosensor production. The creation of two mathematical models to predict monolayer adsorption kinetics and optimal immersion times are discussed. Details are provided of how the new mathematical models may be advanced, and how the production of immunosensors may be further improved. The first novel mathematical model (PTCS) has been created to model the presence of two sequentially forming structures on the surface of a substrate. It gives an insight into the percentages of each structure on the surface, along with the actual adsorption process. This model provides a good fit to all applicable experimental data and has allowed the deduction of optimum immersion times. The second novel model (PIF) provides a greater insight than existing models into the individual contributions to surface coverage by both random and island growth. This allows an insight into how the monolayer surface is covered, which is critical to determine the optimum conditions for adsorption. This model also provides a good fit to the isotherm data it has been applied to. To provide a thorough understanding of the bulk properties of monolayer formation over the gold transducer, and how these properties vary with immersion time and temperature, various measurement techniques have been employed. Electrochemical Impedance Spectroscopy (EIS) has been the principle measurement technique used to measure the bulk properties, but confirmation studies have also been carried out including, Contact angle measurements, FTIR microscopy with BSA molecular labels, Fluorescence microscopy for small adsorbed molecules and AFM for layers assembled from macromolecules. The data generated from the different techniques show consistency with the arguments discussed in each instance. Two different IgG adsorption processes have been compared. These include direct IgG addition and a multilayered streptavidin-based process. The results indicate that IgG molecules adsorbed via the streptavidin based multilayer process are more vertically orientated and have a higher packing density of IgG molecules. Keywords: Self Assembled Monolayer, impedance-based immunoassay, Streptavidin, biotinylated IgG, mathematical adsorption modelling.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 162-172).