[Regulation of the biosynthesis of branched aminoacyl tRNA synthetases in Bacillus cereus T].
The regulation of the biosynthesis of isoleucyl-, valyl-, and leucyl-tRNA synthetases was studied with an isoleucine-valine requiring mutant of Bacillus cereus T. It was shown that valyl-tRNA synthetase regulation is under multivalent control involving both valine and isoleucine. The isoleucyl- and leucyl-tRNA synthetases are repressed by the respective cognate amino acid. When two amino acids were removed from the culture medium, derepression of the two corresponding aminoacyl tRNA synthetases was expected, but only one appears. With a threonine deaminase constitutive mutant, it was demonstrated that the derepression mecanism of the synthetase was correlated with the intracellular level of the ilv A gene product. These results are in good agreement with the model proposed by several authors. In this model, threonine deaminase, or some form of this enzyme, is involved in a positive control of the regulation of the branched-chain aminoacyltransfer ribonucleic acid synthetases.
D000604:Amino Acyl-tRNA Synthetases / Q000096:biosynthesis*; D001409:Bacillus cereus / Q000201:enzymology*; D007532:Isoleucine / Q000494:pharmacology; D007533:Isoleucine-tRNA Ligase / Q000096:biosynthesis; D007930:Leucine / Q000494:pharmacology; D007935:Leucine-tRNA Ligase / Q000096:biosynthesis; D013913:Threonine Dehydratase / Q000378:metabolism; D014633:Valine / Q000494:pharmacology; D014637:Valine-tRNA Ligase / Q000096:biosynthesis
D007532:Isoleucine; D013913:Threonine Dehydratase; D000604:Amino Acyl-tRNA Synthetases; D007935:Leucine-tRNA Ligase; D007533:Isoleucine-tRNA Ligase; D014637:Valine-tRNA Ligase; D007930:Leucine; D014633:Valine
Régulation de la biosynthèse des aminoacyl tRNA synthétases des acides aminés branchés chez Bacillus cereus T.