Tyr‐426 of the Escherichia coli asparaginyl‐tRNA synthetase, an amino acid in a C‐terminal concerved motif, is involved in ATP binding

FEBS Letters

Härtlein, Michael¹  Anselme, Jocelyne¹ 

[1] European Molecular Biology Labaratory, 38042 Grenoble Cedex, France

关键词: Sequence homology;    Aminoacyl-tRNA synthetase;    Site-directed mutagenesis;    ATP binding;    FPLC;    fast protein liquid chromatography;    k cat;    catalytic rate constant;    K m;    Michaelis constant;    SDS;    sodium dodecyl sulphate;   

DOI  :  10.1016/0014-5793(91)80228-U

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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.

【 授权许可】

Unknown