IUBMB Enzyme Nomenclature

EC 6.3.5.6

Accepted name: asparaginyl-tRNA synthase (glutamine-hydrolysing)

Reaction: ATP + aspartyl-tRNAAsn + L-glutamine = ADP + phosphate + asparaginyl-tRNAAsn + L-glutamate

Other name(s): Asp-AdT; Asp-tRNAAsn amidotransferase; aspartyl-tRNAAsn amidotransferase; Asp-tRNAAsn:L-glutamine amido-ligase (ADP-forming)

Systematic name: aspartyl-tRNAAsn:L-glutamine amido-ligase (ADP-forming)

Comments: This reaction forms part of a two-reaction system for producing asparaginyl-tRNA in Deinococcus radiodurans and other organisms lacking a specific enzyme for asparagine synthesis. In the first step, a non-discriminating ligase (EC 6.1.1.23, aspartate—tRNAAsn ligase) mischarges tRNAAsn with aspartate, leading to the formation of aspartyl-tRNAAsn. The aspartyl-tRNAAsn is not used in protein synthesis until the present enzyme converts it into asparaginyl-tRNAAsn (aspartyl-tRNAAsp is not a substrate for this reaction). Ammonia or asparagine can substitute for the preferred substrate glutamine.

Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 37211-76-0

References:

1. Min, B., Pelaschier, J.T., Graham, D.E., Tumbula-Hansen, D. and Söll, D. Transfer RNA-dependent amino acid biosynthesis: an essential route to asparagine formation. Proc. Natl. Acad. Sci. USA 99 (2002) 2678-2683. [PMID: 11880622]

2. Curnow, A.W., Tumbula, D.L., Pelaschier, J.T., Min, B. and Söll, D. Glutamyl-tRNAGln amidotransferase in Deinococcus radiodurans may be confined to asparagine biosynthesis. Proc. Natl. Acad. Sci. USA 95 (1998) 12838-12843. [PMID: 9789001]

3. Ibba, M. and Söll, D. Aminoacyl-tRNA synthesis. Annu. Rev. Biochem. 69 (2000) 617-650. [PMID: 10966471]

[EC 6.3.5.6 created 2002]


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