1zjw: Difference between revisions
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[[Image: | ==Glutaminyl-tRNA synthetase complexed to glutamine and 2'deoxy A76 glutamine tRNA== | ||
<StructureSection load='1zjw' size='340' side='right' caption='[[1zjw]], [[Resolution|resolution]] 2.50Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1zjw]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ZJW OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1ZJW FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=AMP:ADENOSINE+MONOPHOSPHATE'>AMP</scene>, <scene name='pdbligand=GLN:GLUTAMINE'>GLN</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene><br> | |||
<tr><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">glnS ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli])</td></tr> | |||
<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Glutamine--tRNA_ligase Glutamine--tRNA ligase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.1.1.18 6.1.1.18] </span></td></tr> | |||
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1zjw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1zjw OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1zjw RCSB], [http://www.ebi.ac.uk/pdbsum/1zjw PDBsum]</span></td></tr> | |||
<table> | |||
== Evolutionary Conservation == | |||
[[Image:Consurf_key_small.gif|200px|right]] | |||
Check<jmol> | |||
<jmolCheckbox> | |||
<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/zj/1zjw_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | |||
<text>to colour the structure by Evolutionary Conservation</text> | |||
</jmolCheckbox> | |||
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/chain_selection.php?pdb_ID=2ata ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Glutaminyl-tRNA synthetase generates Gln-tRNA(Gln) 10(7)-fold more efficiently than Glu-tRNA(Gln) and requires tRNA to synthesize the activated aminoacyl adenylate in the first step of the reaction. To examine the role of tRNA in amino acid activation more closely, several assays employing a tRNA analog in which the 2'-OH group at the 3'-terminal A76 nucleotide is replaced with hydrogen (tRNA(2'HGln)) were developed. These experiments revealed a 10(4)-fold reduction in kcat/Km in the presence of the analog, suggesting a direct catalytic role for tRNA in the activation reaction. The catalytic importance of the A76 2'-OH group in aminoacylation mirrors a similar role for this moiety that has recently been demonstrated during peptidyl transfer on the ribosome. Unexpectedly, tracking of Gln-AMP formation utilizing an alpha-32P-labeled ATP substrate in the presence of tRNA(2'HGln) showed that AMP accumulates 5-fold more rapidly than Gln-AMP. A cold-trapping experiment revealed that the nonenzymatic rate of Gln-AMP hydrolysis is too slow to account for the rapid AMP formation; hence, the hydrolysis of Gln-AMP to form glutamine and AMP must be directly catalyzed by the GlnRS x tRNA(2'HGln) complex. This hydrolysis of glutaminyl adenylate represents a novel reaction that is directly analogous to the pre-transfer editing hydrolysis of noncognate aminoacyl adenylates by editing synthetases such as isoleucyl-tRNA synthetase. Because glutaminyl-tRNA synthetase does not possess a spatially separate editing domain, these data demonstrate that a pre-transfer editing-like reaction can occur within the synthetic site of a class I tRNA synthetase. | |||
tRNA-dependent aminoacyl-adenylate hydrolysis by a nonediting class I aminoacyl-tRNA synthetase.,Gruic-Sovulj I, Uter N, Bullock T, Perona JJ J Biol Chem. 2005 Jun 24;280(25):23978-86. Epub 2005 Apr 20. PMID:15845536<ref>PMID:15845536</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | ==See Also== | ||
*[[Aminoacyl tRNA Synthetase|Aminoacyl tRNA Synthetase]] | *[[Aminoacyl tRNA Synthetase|Aminoacyl tRNA Synthetase]] | ||
== References == | |||
== | <references/> | ||
< | __TOC__ | ||
</StructureSection> | |||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Glutamine--tRNA ligase]] | [[Category: Glutamine--tRNA ligase]] | ||
Revision as of 05:38, 29 September 2014
Glutaminyl-tRNA synthetase complexed to glutamine and 2'deoxy A76 glutamine tRNAGlutaminyl-tRNA synthetase complexed to glutamine and 2'deoxy A76 glutamine tRNA
Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedGlutaminyl-tRNA synthetase generates Gln-tRNA(Gln) 10(7)-fold more efficiently than Glu-tRNA(Gln) and requires tRNA to synthesize the activated aminoacyl adenylate in the first step of the reaction. To examine the role of tRNA in amino acid activation more closely, several assays employing a tRNA analog in which the 2'-OH group at the 3'-terminal A76 nucleotide is replaced with hydrogen (tRNA(2'HGln)) were developed. These experiments revealed a 10(4)-fold reduction in kcat/Km in the presence of the analog, suggesting a direct catalytic role for tRNA in the activation reaction. The catalytic importance of the A76 2'-OH group in aminoacylation mirrors a similar role for this moiety that has recently been demonstrated during peptidyl transfer on the ribosome. Unexpectedly, tracking of Gln-AMP formation utilizing an alpha-32P-labeled ATP substrate in the presence of tRNA(2'HGln) showed that AMP accumulates 5-fold more rapidly than Gln-AMP. A cold-trapping experiment revealed that the nonenzymatic rate of Gln-AMP hydrolysis is too slow to account for the rapid AMP formation; hence, the hydrolysis of Gln-AMP to form glutamine and AMP must be directly catalyzed by the GlnRS x tRNA(2'HGln) complex. This hydrolysis of glutaminyl adenylate represents a novel reaction that is directly analogous to the pre-transfer editing hydrolysis of noncognate aminoacyl adenylates by editing synthetases such as isoleucyl-tRNA synthetase. Because glutaminyl-tRNA synthetase does not possess a spatially separate editing domain, these data demonstrate that a pre-transfer editing-like reaction can occur within the synthetic site of a class I tRNA synthetase. tRNA-dependent aminoacyl-adenylate hydrolysis by a nonediting class I aminoacyl-tRNA synthetase.,Gruic-Sovulj I, Uter N, Bullock T, Perona JJ J Biol Chem. 2005 Jun 24;280(25):23978-86. Epub 2005 Apr 20. PMID:15845536[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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