Date of Award


Publication Type

Master Thesis

Degree Name



Chemistry and Biochemistry


Chemistry, Biochemistry.


Szabo, A. G.,




Tryptophanyl-tRNA synthetase (TrpRS) is the key enzyme responsible for the aminoacylation of t-RNATrp with tryptophan (Trp). Previously, in our lab, B. subtilis TrpRS wild type and its Trp analogue incorporated mutants were prepared. Their characteristics and the structural similarities were studied. To determine whether the single tryptophan, W92 can be replaced by another amino acid, mutants were prepared where W92 was substituted by Tyrosine. This is suggested by the sequence of the M. genitalium TrpRS, which has a tyrosine in position 92. Thus, we have prepared B. subtilis TrpRS mutants W92Y and W92YI46F, and examined some of their properties. The relative activity and the structural differences of these mutants is discussed. The work on TrpRS has been extended to B. stearothermophilus TrpRS, which has three Trp residues. The B. stearothermopolis mutants, W91Y, W48Y, W48Y W91Y and W48YW91YW290Y were prepared and their activities and structural properties were measured using different optical spectroscopic techniques such as circular dichroism, fluorescence and absorbance. The complex TrpRS Trp-adenylates of the above enzymes have been isolated using different Trp analogues and ATP. The unfolding mechanism of some of these proteins were studied using the fluorescence of tryptophan or 7-azatryptophan.Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1998 .R35. Source: Masters Abstracts International, Volume: 39-02, page: 0510. Adviser: A. G. Szabo. Thesis (M.Sc.)--University of Windsor (Canada), 1998.