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Identification of residues involved in the binding of methionine by Escherichia coli methionyl‐tRNA synthetase
Author(s) -
Daniel Fourmy,
Yves Mechulam,
Simone Brunie,
Sylvain Blanquet,
Guy Fayat
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)80879-8
Subject(s) - escherichia coli , methionine , transfer rna , biochemistry , chemistry , biology , amino acid , rna , gene
Comparison of the amino‐acid sequences of several methionyl‐tRNA synthetases indicates the occurrence of a few conserved motifs, having a possible functional significance. The role of one of these motifs, centered at position 300 in the E. coli enzyme sequence, was assayed by the use of site‐directed mutagenesis. Substitution of the His 301 or Trp 305 residues by Ala resulted in a large decrease in methionine affinity, whereas the change of Val 298 into Ala had only a moderate effect. The catalytic rate of the enzyme was unimpaired by these substitutions. It is concluded that the above conserved amino‐acid region is located at or close to the amino‐acid binding pocket of methionyl‐tRNA synthetase.