The asparagine-transamidosome from Helicobacter pylori : a dual-kinetic mode in non-discriminating aspartyl-tRNA synthetase safeguards the genetic code

Fischer, Frédéric; Huot, Jonathan L.; Lorber, Bernard; Diss, Guillaume; Hendrickson, Tamara L.; Becker, Hubert Dominique; Lapointe, Jacques; Kern, Daniel

doi:10.1093/nar/gks167

Cited by 21 publications

(32 citation statements)

References 51 publications

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“…The K m value of GatCAB wt for Asp-tRNA Asn (1.67 mM) resembles that of H. pylori GatCAB (1.12 mM) for Asp-tRNA Asn (Fig. 4, Table 1) (Fischer et al, 2012).…”

Section: Overproduction and Purification Of M Catarrhalis Gatcabsmentioning

confidence: 63%

Natural insertion of the bro-1 β-lactamase gene into the gatCAB operon affects Moraxella catarrhalis aspartyl-tRNAAsn amidotransferase activity

2012

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Only about half of bacterial species use an asparaginyl-tRNA synthetase (AsnRS) to attach Asn to its cognate tRNA Asn . Other bacteria, including the human pathogen Moraxella catarrhalis, a causative agent of otitis media, lack a gene encoding AsnRS, and form Asn-tRNA Asn by an indirect pathway catalysed by two enzymes: first, a non-discriminating aspartyl-tRNA synthetase (ND-AspRS) catalyses the formation of aspartyl-tRNA Asn (Asp-tRNA Asn ); then, a tRNAdependent amidotransferase (GatCAB) transamidates this 'incorrect' product into Asn-tRNA Asn . As M. catarrhalis has a Gln-tRNA synthetase, its GatCAB functions as an Asp-tRNA Asn amidotransferase. This pathogen rapidly evolved to about 90 % ampicillin resistance worldwide by insertion of a bro-1 b-lactamase gene within the gatCAB operon. Comparison of the GatCAB subunits from bro-1 b-lactamase-positive and bro-negative strains showed that the laterally transferred bro-1 gene, inserted into the gatCAB operon, affected the C-terminal sequence of GatA. The identity between the C-terminal sequences of GatA wt (residues 479-491) and of GatA BRO-1 (residues 479-492) was about 36 %, whereas the rest of the GatA sequence was relatively conserved. The characterization of these two distinct GatCABs as well as the hybrid GatCAB containing GatA(1-478) wt (479-492) BRO-1 and truncated GatCAB enzymes of M. catarrhalis showed that the substitution in GatA wt of residues 479-492 of GatA BRO-1 causes increased specificity for glutamine, and decreased specificity for Asp-tRNA Asn in the transamidation reaction. We conclude that the bro gene insertion has altered the kinetic parameters of Asp-tRNA Asn amidotransferase, and we propose a model for gatA evolution after the insertion of bro-1 at the carboxyl end of gatA.

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“…The K m value of GatCAB wt for Asp-tRNA Asn (1.67 mM) resembles that of H. pylori GatCAB (1.12 mM) for Asp-tRNA Asn (Fig. 4, Table 1) (Fischer et al, 2012).…”

Section: Overproduction and Purification Of M Catarrhalis Gatcabsmentioning

confidence: 63%

Natural insertion of the bro-1 β-lactamase gene into the gatCAB operon affects Moraxella catarrhalis aspartyl-tRNAAsn amidotransferase activity

2012

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“…(ii) The Gln and Asn transamidosomes in Helicobacter pylori are transiently formed in the presence of tRNA Gln and tRNA Asn , respectively (32,33). A protein component Hp0100 can facilitate the formation of a stable Asn transamidosome in H. pylori (34).…”

Section: Discussionmentioning

confidence: 99%

Ancient translation factor is essential for tRNA-dependent cysteine biosynthesis in methanogenic archaea

Liu¹,

Nakamura²,

Nakazawa

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Significance Translation requires aminoacyl-tRNAs that are mainly formed by acylating tRNAs with the corresponding amino acids. Methanogenic archaea synthesize Cys-tRNA in an unusual indirect fashion. They attach a precursor amino acid, phosphoserine, to tRNA Cys , which is then converted to cysteine. This study shows that the indirect Cys-tRNA formation is carried out in a multienzyme complex assembled by a translation factor. Complex formation markedly promotes reaction efficiency. Because the indirect Cys-tRNA formation is the ancestral pathway of Cys biosynthesis in archaea, this complex may represent a remnant of a primordial machinery for Cys coding.

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“…AdT, ND-AspRS, and Hp0100, a Protein of Unknown Function-In contrast to the stable, tRNAdependent Asn-transamidosome from T. thermophilus, an analogous H. pylori Asn-transamidosome could not be isolated (15). We investigated the possibility that a protein of unknown function is needed to promote assembly of a more stable complex.…”

Section: Published Yeast Two-hybrid Results Suggest Biologically Signmentioning

confidence: 99%

“…1C, lane 5) (15). We recently showed that the H. pylori Asn-transamidosome is dynamic and unstable (15).…”

Section: Hp0100 Adt and Nd-asprs Assemble Into Binary And Ternary Cmentioning

confidence: 94%

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A tRNA-independent Mechanism for Transamidosome Assembly Promotes Aminoacyl-tRNA Transamidation

Silva

Fatma

Floyd

et al. 2013

Journal of Biological Chemistry

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The asparagine-transamidosome from Helicobacter pylori : a dual-kinetic mode in non-discriminating aspartyl-tRNA synthetase safeguards the genetic code

Cited by 21 publications

References 51 publications

Natural insertion of the bro-1 β-lactamase gene into the gatCAB operon affects Moraxella catarrhalis aspartyl-tRNAAsn amidotransferase activity

Natural insertion of the bro-1 β-lactamase gene into the gatCAB operon affects Moraxella catarrhalis aspartyl-tRNAAsn amidotransferase activity

Ancient translation factor is essential for tRNA-dependent cysteine biosynthesis in methanogenic archaea

A tRNA-independent Mechanism for Transamidosome Assembly Promotes Aminoacyl-tRNA Transamidation

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