Akademisk avhandling--Gothenburg. / Extra t.p., with thesis statement, inserted. Bibliography: p. 23-24.

Akademisk avhandling--Gothenburg. / Extra t.p., with thesis statement, inserted. Bibliography: p. 23-24.

Thesis (Ph. D.) -- California Institute of Technology, 2009. / Advisor and committee chair names found in the thesis' metadata record in the digital repository. Title from home page (viewed 06/21/2010). Includes bibliographical references.

The aminoacyl-tRNA synthetases are a family of enzymes involved in the process of translation, more specifically, ligating amino acids to their cognate tRNA molecules. Recent evidence suggests that aminoacyl-tRNA synthetases are capable of aminoacylating proteins, some of which are involved in the autophagy pathway. Here, we test the conditions under which E. coli and human threonyl-tRNA synthetases, as well as hisidyl-tRNA synthetase aminoacylate themselves. These reactions are ATP dependent, stimulated by Mg2+, and are inhibited by increasing cognate tRNA concentrations. These data represent the foundation for future aminoacylation experiments, specifically delving into the relationship between the autophagy pathway and the aminoacylation of proteins. Additionally, we provide evidence of the inhibitory abilities of the compound EHTS-0 on both E. coli and human threonyl-tRNA synthetases. Further, we also show that an EHTS-0 analog, EHTS-1, also significantly inhibits E. coli threonyl-tRNA synthetase but not the human enzyme. These data could be useful in determining the potential for EHTS-0 and EHTS-1 as possibly anti-angiogenic drugs.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 171-191).

No description available.

The aminoacyl-tRNA synthetases (aaRSs) are the universal set of enzymes responsible for attaching amino acids to tRNA to be used as substrates in the process of protein translation. As these enzymes act at the transition between nucleic acids and proteins, their specificity of action is critical for maintaining the fidelity of the genetic code. From a mechanistic standpoint, aaRS specificity is enforced by a complex series of tRNA structural and chemical elements that collectively make up its identity set and serve to distinguish one tRNA from another. Based on sequence, structure, and oligomeric differences, the aaRS family has been partitioned into two classes, each of which is responsible for roughly half of the 22 genetically encoded amino acids. In the studies presented here, pre-steady-state kinetic methods were employed to measure individual events that collectively make up the catalytic cycle of the class II Escherichia coli Histidyl-tRNA Synthetase (HisRS) in order to elucidate the nature of its enzymatic activity and determine how these events contribute to the exquisite specificity between enzyme and tRNA. The results presented here indicate indentiy elements of tRNAHis regulate the activity of the amino acid activation and aminoacyl transfer half reactions. Additional evidence suggests communication between active sites of the HisRS homodimer plays a role in establishing an alternating cycle of catalysis in the steady state.

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Plant Biology." Includes bibliographical references (p. 178-184).

Several Saccharomyces cerevisiae mutant tRNAQ2 species (glutamine isoacceptor, CUG anticodon) were synthesized and assayed for aminoacylation activity with Saccharomyces cerevisiae glutaminyl-tRNA synthetase. The derived steady state parameters were compared to similar datasets from the literature. The mutants behaved analogously to similar mutant species based on tRNA from Escherichia coli, but with slightly relaxed specificity as revealed by comparison of kcat/KM values relative to wild type in vitro transcribed tRNA. Additionally the eukaryotic N-terminal domain appendage, as found in Sce glutaminyl-tRNA synthetase, is considered in light of the discovery of non-canonical aminoacyl-tRNA synthetase functions, including its role in the assembly of the multiple aminoacyl-tRNA synthetase complex.

No description available.