EcoliWiki - User contributions [en]

PMID:19965768

2009-12-14T22:04:04Z

124.212.197.42: Fill PMID: Page!

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 '''Kimura, S and Suzuki, T''' (2009) Fine-tuning of the ribosomal decoding center by conserved methyl-modifications in the Escherichia coli 16S rRNA.''Nucleic Acids Res.'' 

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|{{TableHeadingColor}} |'''Abstract''' || <protect>In bacterial 16S rRNAs, methylated nucleosides are clustered within the decoding center, and these nucleoside modifications are thought to modulate translational fidelity. The N(4), 2'-O-dimethylcytidine (m(4)Cm) at position 1402 of the Escherichia coli 16S rRNA directly interacts with the P-site codon of the mRNA. The biogenesis and function of this modification remain unclear. We have identified two previously uncharacterized genes in E. coli that are required for m(4)Cm formation. mraW (renamed rsmH) and yraL (renamed rsmI) encode methyltransferases responsible for the N(4) and 2'-O-methylations of C1402, respectively. Recombinant RsmH and RsmI proteins employed the 30S subunit (not the 16S rRNA) as a substrate to reconstitute m(4)Cm1402 in the presence of S-adenosylmethionine (Ado-Met) as the methyl donor, suggesting that m(4)Cm1402 is formed at a late step during 30S assembly in the cell. A luciferase reporter assay indicated that the lack of N(4) methylation of C1402 increased the efficiency of non-AUG initiation and decreased the rate of UGA read-through. These results suggest that m(4)Cm1402 plays a role in fine-tuning the shape and function of the P-site, thus increasing decoding fidelity.</protect>
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|{{TableHeadingColor}} nowrap |'''Links''' || [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=19965768 PubMed] Online version:[http://dx.doi.org/10.1093/nar/gkp1073 10.1093/nar/gkp1073]
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!|Gene product!!Qualifier!!GO ID!!GO term name!!Evidence Code!!with/from!!Aspect!!Notes!!Status

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PMID:19965768

2009-12-14T22:04:04Z

124.212.197.42: New PMID: Page!

PMID:19944692

2009-12-14T22:02:39Z

124.212.197.42: Fill PMID: Page!

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 '''Suzuki, T and Miyauchi, K''' (2009) Discovery and characterization of tRNA(Ile) lysidine synthetase (TilS).''FEBS Lett.'' 

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|{{TableHeadingColor}} |'''Abstract''' || <protect>In the bacterial decoding system, the AUA codon is deciphered as isoleucine by tRNA(Ile) bearing lysidine (L, 2-lysyl-cytidine) at the wobble position. Lysidine is an essential modification that determines both the codon and amino acid specificities of tRNA(Ile). We identified an enzyme named tRNA(Ile) lysidine synthetase (TilS) that catalyzes lysidine formation by using lysine and ATP as substrates. Biochemical studies revealed a molecular mechanism of lysidine formation that consists of two consecutive reactions involving the adenylated tRNA intermediate. In addition, we deciphered how Escherichia coli TilS specifically discriminates between tRNA(Ile) and the structurally similar tRNA(Met), which bears the same anticodon loop. Recent structural studies unveiled tRNA recognition by TilS, and a molecular basis of lysidine formation at atomic resolution.</protect>
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|{{TableHeadingColor}} nowrap |'''Links''' || [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=19944692 PubMed] Online version:[http://dx.doi.org/10.1016/j.febslet.2009.11.085 10.1016/j.febslet.2009.11.085]
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==Significance {{HelpIcon|Help:Literature}} ==
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== Useful Materials and Methods {{HelpIcon|Help:Literature}}==
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==Annotations {{HelpIcon|Help:Literature}}==
<protect>

{|class = 'sortable' border="2" cellpadding="4" cellspacing="0" style="margin: 1em 1em 1em 0; border: 1px #aaa solid; border-collapse: collapse;"
|- {{table heading style}}
!|Gene product!!Qualifier!!GO ID!!GO term name!!Evidence Code!!with/from!!Aspect!!Notes!!Status

|-class='sortbottom'
|[{{SERVER}}{{SCRIPTPATH}}?title=Special:TableEdit&id=63ce1649aab8b3180235b0af7618f667.170022.K4b26b5ff6d871&page=170022&pagename={{FULLPAGENAMEE}}&type=0&template=GO_table_reference edit table] || || || || || || || ||
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==References==
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PMID:19944692

2009-12-14T22:02:39Z

124.212.197.42: New PMID: Page!