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Tyr‐426 of the Escherichia coli asparaginyl‐tRNA synthetase, an amino acid in a C‐terminal concerved motif, is involved in ATP binding
Author(s) -
Anselme Jocelyne,
Härtlein Michael
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)80228-u
Subject(s) - escherichia coli , transfer rna , biochemistry , enzyme , aminoacyl trna synthetase , biology , nucleotide , amino acid , peptide sequence , binding site , site directed mutagenesis , mutant , rna , gene
Sequence comparisons of the E. Coli asparaginyl‐tRNA synthetase (NRSEC) with aminoacyl‐tRNA synthetase sequences of class II enzymes show significant homologies with aspartyl‐ and lysyl‐tRNA synthetases. Three conserved regions were found, one of which is located in the C‐terminal part of the NRSEC sequence. Site‐directed mutagenesis was performed in this conserved region. A single point mutation Tyr‐426→Ser results in a 15‐fold increase in the K m for ATP, while all the other kinetic parameters remain unchanged. The replacement of this Tyr‐426 by a Phe does not affect the behavior of the enzyme. These data indicate that Tyr‐426 is part of the ATP binding site.