The isolation of a peptide from the catalytic domain of Bacillus stearothermophilus tryptophyl-tRNA synthetase. The interaction of Brown MX-5BR with tyrosyl-tRNA synthetase.
Tryptophyl-tRNA synthetase is irreversibly inactivated by Procion Brown MX-5BR with an apparent dissociation constant (KD) of 8.8 microM and maximum rate of inactivation k3 0.192 s-1. The specificity of the interaction is supported by two previously reported observations. Firstly, Brown MX-5BR inactivation of tryptophyl-tRNA synthetase is inhibited by substrates, and secondly, the animated derivative of Brown MX-5BR is a competitive inhibitor of tryptophyl-tRNA synthetase with a Ki of 2 X 10(-4) M with respect to both tryptophan and ATP. Tryptic digestion of the dye-affinity-labelled enzyme and subsequent resolution of the peptides by h.p.l.c. yielded one major dye-peptide peak. Amino acid sequence analysis resulted in the identification of the dye-binding domain centred on lysine-178. Tyrosyl-tRNA synthetase is also inactivated by Procion Brown MX-5BR, and this inactivation is prevented by ATP but not by tyrosine. The interaction of tyrosyl-tRNA synthetase with hydroxylated Brown MX-5BR exhibited non-competitive kinetics with respect to the amino acid-binding site and competitive kinetics against ATP with a Ki of 6 X 10(-6) M.
McArdell
J E
JE
Public Health Laboratory Service, Centre for Applied Microbiology and Research, Porton Down, Wilts, U.K.
Bruton
C J
CJ
Atkinson
T
T
D000595:Amino Acid Sequence; D000604:Amino Acyl-tRNA Synthetases / Q000037:antagonists & inhibitors*; D002851:Chromatography, High Pressure Liquid; D004396:Coloring Agents / Q000494:pharmacology*; D001411:Geobacillus stearothermophilus / Q000201:enzymology*; D010446:Peptide Fragments / Q000302:isolation & purification*; D014227:Triazines; D014369:Tryptophan-tRNA Ligase / Q000037:antagonists & inhibitors*
D004396:Coloring Agents; D010446:Peptide Fragments; D014227:Triazines; C053802:Procion Brown MX 5BR; D000604:Amino Acyl-tRNA Synthetases; D014369:Tryptophan-tRNA Ligase