A unique insert of leucyl-tRNA synthetase is required for aminoacylation and not amino acid editing.

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Vu MT, Martinis SA

A unique insert of leucyl-tRNA synthetase is required for aminoacylation and not amino acid editing.

Biochemistry. 2007 May 1;46(17):5170-6. Epub 2007 Apr 4.

PubMed ID
17407263 [ View in PubMed
]
Abstract

Leucyl-tRNA synthetase (LeuRS) is a class I enzyme, which houses its aminoacylation active site in a canonical core that is defined by a Rossmann nucleotide binding fold. In addition, many LeuRSs bear a unique polypeptide insert comprised of about 50 amino acids located just upstream of the conserved KMSKS sequence. The role of this leucine-specific domain (LS-domain) remains undefined. We hypothesized that this domain may be important for substrate recognition in aminoacylation and/or amino acid editing. We carried out a series of deletion mutations and chimeric swaps within the leucine-specific domain of Escherichia coli. Our results support that the leucine-specific domain is critical for aminoacylation but not required for editing activity. Kinetic analysis determined that deletion of the LS-domain primarily impacts kcat. Because of its proximity to the aminoacylation active site, we propose that this domain interacts with the tRNA during amino acid activation and/or tRNA aminoacylation. Although the leucine-specific domain does not appear to be important to the editing complex, it remains possible that it aids the dynamic translocation process that moves tRNA from the aminoacylation to the editing complex.

DrugBank Data that Cites this Article

Drug Targets
DrugTargetKindOrganismPharmacological ActionActions
LeucineLeucine--tRNA ligase, cytoplasmicProteinHumans
Unknown
Not AvailableDetails
LeucineProbable leucine--tRNA ligase, mitochondrialProteinHumans
Unknown
Not AvailableDetails