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. 2002 Mar 5;99(5):2678-83.
doi: 10.1073/pnas.012027399.

Transfer RNA-dependent amino acid biosynthesis: an essential route to asparagine formation

Bokkee Min  1 , Joanne T Pelaschier, David E Graham, Debra Tumbula-Hansen, Dieter Söll
Affiliations

Transfer RNA-dependent amino acid biosynthesis: an essential route to asparagine formation

Bokkee Min et al. Proc Natl Acad Sci U S A. .

Abstract

Biochemical experiments and genomic sequence analysis showed that Deinococcus radiodurans and Thermus thermophilus do not possess asparagine synthetase (encoded by asnA or asnB), the enzyme forming asparagine from aspartate. Instead these organisms derive asparagine from asparaginyl-tRNA, which is made from aspartate in the tRNA-dependent transamidation pathway [Becker, H. D. & Kern, D. (1998) Proc. Natl. Acad. Sci. USA 95, 12832-12837; and Curnow, A. W., Tumbula, D. L., Pelaschier, J. T., Min, B. & Söll, D. (1998) Proc. Natl. Acad. Sci. USA 95, 12838-12843]. A genetic knockout disrupting this pathway deprives D. radiodurans of the ability to synthesize asparagine and confers asparagine auxotrophy. The organism's capacity to make asparagine could be restored by transformation with Escherichia coli asnB. This result demonstrates that in Deinococcus, the only route to asparagine is via asparaginyl-tRNA. Analysis of the completed genomes of many bacteria reveal that, barring the existence of an unknown pathway of asparagine biosynthesis, a wide spectrum of bacteria rely on the tRNA-dependent transamidation pathway as the sole route to asparagine.

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Figures

Figure 1
Figure 1
Redundant pathways of Asn-tRNAAsn synthesis in D. radiodurans. Shown are the direct pathway (top half of diagram) and the transamidation pathway (bottom half of diagram).
Figure 2
Figure 2
Asp-tRNA formation by the two D. radiodurans AspRS enzymes. AspRS1 (●) and AspRS2 (○) were used to aminoacylate, per reaction, unfractionated D. radiodurans tRNA (A, 800 pmol), D. radiodurans tRNAAsn transcript (B, 40 pmol), and D. radiodurans tRNAAsp transcript (C, 40 pmol).
Figure 3
Figure 3
Growth properties of D. radiodurans strain constructs. ΔaspS2, aspS2 deletion strain; WT, wild-type parent strain; ΔaspS2/asnB, aspS2 deletion strain complemented in trans with E. coli asnB; ΔasnS, asnS deletion strain. Growth on minimal agar plates in the presence (+Asn) or absence (−Asn) of asparagine is shown.
Figure 4
Figure 4
Coexpression of D. radiodurans aspS2 and gatCAB genes rescues asparagine auxotrophy of E. coli strain JF448. Growth on minimal agar plates in the presence (+Asn) or absence (−Asn) of asparagine is shown. The complementing genes were introduced on the pCYB1 vector.
Figure 5
Figure 5
Phylogeny of AsnB homologs. Bootstrap percentages for each branch were estimated by the resampling estimated log-likelihood method. (Scale bar represents 10 substitutions per 100 aa positions.)
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References

    1. Milman H A, Cooney D A. Biochem J. 1979;181:51–59. - PMC - PubMed
    1. Zalkin H, Truitt C D. J Biol Chem. 1977;252:5431–5436. - PubMed
    1. Nakamura M, Yamada M, Hirota Y, Sugimoto K, Oka A, Takanami M. Nucleic Acids Res. 1981;9:4669–4676. - PMC - PubMed
    1. Scofield M A, Lewis W S, Schuster S M. J Biol Chem. 1990;265:12895–12902. - PubMed
    1. Richards N G, Schuster S M. Adv Enzymol Relat Areas Mol Biol. 1998;72:145–198. - PubMed

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