Bibliography: leaves 187-202 / 204 leaves ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Organic Chemistry, 1991

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Joseph M. Fox, Dept. of Chemistry & Biochemistry. Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 1977. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

With the objective to functionalize proteins for the understanding of their biological roles and developing protein-based biosensors, I have been developing methods to synthesize proteins with defined modifications and applying them to study protein functional roles and generate proteins with new properties. These methods rely on the read-through of an in-frame stop codon in mRNA by a nonsense suppressor tRNA specifically acylated with a noncanoncial amino acid (NAA) by a unique aminoacyl-tRNA synthetase and the genetic incorporation of this NAA at the stop codon site. NAAs either provide chemical handles for site-specific manipulation or mimic the posttranslational modifications, which are critical for understanding cellular regulations and signal transduction. The pyrrolysine synthetase (PylRS) has been wildly used to incorporate NAAs into proteins in E. coli. Taking advantage of PylRS, I have developed method to genetically incorporate ketone-containing N--acetyl-L-lysine analog, 2-amino-8-oxononanoic acid (KetoK), into proteins for their site-specific modifications and used it to mimic the protein lysine acetylation process. I have also modified the ribosome in order to improve the amber suppression efficiency and therefore to achieve incorporation of multiple copies of NAA into one protein. By overexpressing a truncated ribosomal protein, L11C, I have demonstrated 5-fold increase of amber suppression level in E. coli, leading to higher expression levels for proteins incorporated with NAAs. I have also demonstrated this method can be applied successfully to incorporate at least 3 NAAs into one protein in E. coli. With the success of incorporating multiple NAAs into one protein, I have further introduced two distinct NAAs into one protein simultaneously. This is done by using a wild type or evolved PylRS-pylTUUA pair and an evolved M. jannaschii tyrosyl-tRNA synthetase (MjTyrRS)-tRNACUA pair. By suppressing both UAG and UAA stop codons in one mRNA, a protein incorporated with two NAAs is synthesized with a decent yield. There is of great interest to incorporate new NAAs into proteins, which is done by library selection. By introducing both positive and negative selective markers into one plasmid, I have developed a one-plasmid selection method. In this method, the positive and negative selections are accomplished by in a single type of cells hosting a single selection plasmid.

Six Quarter Horse yearling fillies were used in a duplicated 3 x 3 Latin square designed experiment to evaluate the technique of nitrogen retention as a response criterion for amino acid studies in the horse. The yearlings were paired by age and randomly assigned to one of three concentrates fed with a medium quality Coastal Bermudagrass hay throughout the study. Diets were fed at approximately 1.9% of horse body weight per day, divided into twice daily feedings with a 60:40 concentrate: hay ratio. With the exception of lysine and threonine, proposed amino acid requirements for yearling horses were calculated using nutrient to calorie ratios of gilts weighing 80-120 kg and gaining 325 g/d. Diet A was amino acid sufficient, as provided by a soybean meal-based concentrate. Diet B was amino acid deficient, with a cottonseed hull-based concentrate. Diet A and Diet B were isonitrogenous, containing approximately 12% crude protein. Diet C used the identical concentrate as Diet B, with synthetic essential amino acids and cysteine orally dosed to match the amino acid levels in Diet A. Nitrogen retention was not different between Diet A and Diet B. Diet C resulted in differences from Diets A and B in nitrogen retention; however, differences were a consequence of nitrogen intake. Nitrogen retained as a percent of nitrogen absorbed was lower (P < 0.05) for Diet B than for Diet A, for data not accounting for endogenous fecal and urinary losses. There were no differences in nitrogen retained as a percent of nitrogen absorbed for horses fed Diet C, when compared to either Diet A or Diet B, for data not accounting for endogenous losses. It was concluded that differences in nitrogen retained as a percent of nitrogen absorbed were observed between amino acid sufficient diets and amino acid deficient diets. However, horses fed amino acid deficient diets and orally dosed with synthetic amino acids, likely require some modified dosage level to achieve the same or higher values in nitrogen retained as a percent of nitrogen absorbed as those values for amino acid sufficient diets.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: chromophore -- N-ethyl-3-carbazolylalanine -- 9-anthrylalanine -- chiral amino acids -- cyclic peptide -- solid-phase peptide synthesis -- enzymatic resolution -- cyclization. Includes bibliographical references (p. 92-95).

Includes bibliographical references.

Thesis (Ph. D. (Biochemistry & Microbiology))--Rhodes University, 2003.

published_or_final_version / Chemistry / Master / Master of Philosophy