Section 41
Chapter 40,374

Impaired affinity for phenylalanine in Escherichia coli phenylalanyl-tRNA synthetase mutant caused by Gly-to-Asp exchange in motif 2 of class Ii tRNA synthetases

Kast, P.; Wehrli, C.; Hennecke, H.

Febs Letters 293(1-2): 160-163


ISSN/ISBN: 0014-5793
PMID: 1959653
DOI: 10.1016/0014-5793(91)81176-9
Accession: 040373506

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Phenylalanyl-tRNA synthetase (PheRS; alpha 2 beta 2 subunit structure) is a member of class II of tRNA synthetases. We report here the genetic analysis of an Escherichia coli mutant strain which is auxotrophic for phenylalanine because it has a PheRS with a decreased affinity for phenylalanine. The mutant pheS gene encoding the PheRS alpha subunit was cloned and sequenced, and the deviation from the wild-type gene was found to result in a Gly191-to-Asp191 exchange. This alteration is located within motif 2, one of 3 conserved sequence motifs characteristic for class II aminoacyl-tRNA synthetases. Motif 2 may thus participate in the formation of the phenylalanine binding site in PheRS.

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