Open AccessSelection of suppressor methionyl-tRNA synthetases: mapping the tRNA anticodon binding site.
Author(s) -
Thierry Meinnel,
Yves Mechulam,
Daniel Le Corre,
Michel Panvert,
Sylvain Blanquet,
Guy Fayat
Publication year - 1991
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.88.1.291
Subject(s) - transfer rna , aminoacylation , biology , escherichia coli , biochemistry , mutant , methionine , enzyme , aminoacyl trna synthetase , genetics , microbiology and biotechnology , amino acid , rna , gene
Accurate aminoacylation of a tRNA by Escherichia coli methionyl-tRNA synthetase (MTS) is specified by the CAU anticodon. A genetic screening procedure was designed to isolate MTS mutants able to aminoacylate a methionine amber tRNA (CUA anticodon). Selected suppressor MTS enzymes all possess one or several mutations in the vicinity of Trp-461, a residue that is the major contributor to the stability of complexes formed with tRNAs having the cognate CAU anticodon. Analysis of catalytic properties of purified suppressor enzymes shows that they have acquired an additional specificity toward the amber anticodon without complete disruption of the methionine anticodon site. It is concluded that both positive and negative discrimination toward the binding of tRNA anticodon sequences is restricted to a limited region of the synthetase, residues 451-467.