Skip Header

You are using a version of browser that may not display all the features of this website. Please consider upgrading your browser.

Non-discriminating and discriminating aspartyl-tRNA synthetases differ in the anticodon-binding domain.

Charron C., Roy H., Blaise M., Giege R., Kern D.

In most organisms, tRNA aminoacylation is ensured by 20 aminoacyl-tRNA synthetases (aaRSs). In eubacteria, however, synthetases can be duplicated as in Thermus thermophilus, which contains two distinct AspRSs. While AspRS-1 is specific, AspRS-2 is non-discriminating and aspartylates tRNA(Asp) and tRNA(Asn). The structure at 2.3 A resolution of AspRS-2, the first of a non-discriminating synthetase, was solved. It differs from that of AspRS-1 but has resemblance to that of discriminating and archaeal AspRS from Pyrococcus kodakaraensis. The protein presents non-conventional features in its OB-fold anticodon-binding domain, namely the absence of a helix inserted between two beta-strands of this fold and a peculiar L1 loop differing from the large loops known to interact with tRNA(Asp) identity determinant C36 in conventional AspRSs. In AspRS-2, this loop is small and structurally homologous to that in AsnRSs, including conservation of a proline. In discriminating Pyrococcus AspRS, the L1 loop, although small, lacks this proline and is not superimposable with that of AspRS-2 or AsnRS. Its particular status is demonstrated by a loop-exchange experiment that renders the Pyrococcus AspRS non-discriminating.

EMBO J. 22:1632-1643(2003) [PubMed] [Europe PMC]

We'd like to inform you that we have updated our Privacy Notice to comply with Europe’s new General Data Protection Regulation (GDPR) that applies since 25 May 2018.

Do not show this banner again
UniProt is an ELIXIR core data resource
Main funding by: National Institutes of Health