1rfl: Difference between revisions

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'''NMR data driven structural model of G-domain of MnmE protein'''<br />


==Overview==
==NMR data driven structural model of G-domain of MnmE protein==
The Escherichia coli MnmE protein is a 50-kDa multidomain GTPase involved, in tRNA modification. Its homologues in eukaryotes are crucial for, mitochondrial respiration and, thus, it is thought that the human protein, might be involved in mitochondrial diseases. Unlike Ras, MnmE shows a high, intrinsic GTPase activity and requires effective GTP hydrolysis, and not, simply GTP binding, to be functionally active. The isolated MnmE G-domain, (165 residues) conserves the GTPase activity of the entire protein, suggesting that it contains the catalytic residues for GTP hydrolysis. To, explore the GTP hydrolysis mechanism of MnmE, we analyzed the effect of, low pH on binding and hydrolysis of GTP, as well as on the formation of a, MnmE transition state mimic. GTP hydrolysis by MnmE, but not GTP binding, or formation of a complex with mant-GDP and aluminium fluoride, is, impaired at acidic pH, suggesting that the chemistry of the transition, state mimic is different to that of the true transition state, and that, some residue(s), critical for GTP hydrolysis, is severely affected by low, pH. We use a nuclear magnetic resonance (NMR)-based approach to get, insights into the MnmE structure and properties. The combined use of NMR, restraints and homology structural information allowed the determination, of the MnmE G-domain structure in its free form. Chemical shift, structure-based prediction provided a good basis for structure refinement, and validation. Our data support that MnmE, unlike other GTPases, does not, use an arginine finger to drive catalysis, although Arg252 may play a role, in stabilization of the transition state.
<StructureSection load='1rfl' size='340' side='right'caption='[[1rfl]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1rfl]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RFL OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1RFL FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1rfl FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1rfl OCA], [https://pdbe.org/1rfl PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1rfl RCSB], [https://www.ebi.ac.uk/pdbsum/1rfl PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1rfl ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MNME_ECOLI MNME_ECOLI] Exhibits a very high intrinsic GTPase hydrolysis rate. Involved in the addition of a carboxymethylaminomethyl (cmnm) group at the wobble position (U34) of certain tRNAs, forming tRNA-cmnm(5)s(2)U34.
== 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/rf/1rfl_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/main_output.php?pdb_ID=1rfl ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The Escherichia coli MnmE protein is a 50-kDa multidomain GTPase involved in tRNA modification. Its homologues in eukaryotes are crucial for mitochondrial respiration and, thus, it is thought that the human protein might be involved in mitochondrial diseases. Unlike Ras, MnmE shows a high intrinsic GTPase activity and requires effective GTP hydrolysis, and not simply GTP binding, to be functionally active. The isolated MnmE G-domain (165 residues) conserves the GTPase activity of the entire protein, suggesting that it contains the catalytic residues for GTP hydrolysis. To explore the GTP hydrolysis mechanism of MnmE, we analyzed the effect of low pH on binding and hydrolysis of GTP, as well as on the formation of a MnmE transition state mimic. GTP hydrolysis by MnmE, but not GTP binding or formation of a complex with mant-GDP and aluminium fluoride, is impaired at acidic pH, suggesting that the chemistry of the transition state mimic is different to that of the true transition state, and that some residue(s), critical for GTP hydrolysis, is severely affected by low pH. We use a nuclear magnetic resonance (NMR)-based approach to get insights into the MnmE structure and properties. The combined use of NMR restraints and homology structural information allowed the determination of the MnmE G-domain structure in its free form. Chemical shift structure-based prediction provided a good basis for structure refinement and validation. Our data support that MnmE, unlike other GTPases, does not use an arginine finger to drive catalysis, although Arg252 may play a role in stabilization of the transition state.


==About this Structure==
Structural insights into the GTPase domain of Escherichia coli MnmE protein.,Monleon D, Martinez-Vicente M, Esteve V, Yim L, Prado S, Armengod ME, Celda B Proteins. 2007 Feb 15;66(3):726-39. PMID:17143896<ref>PMID:17143896</ref>
1RFL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1RFL OCA].


==Reference==
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
Structural insights into the GTPase domain of Escherichia coli MnmE protein., Monleon D, Martinez-Vicente M, Esteve V, Yim L, Prado S, Armengod ME, Celda B, Proteins. 2007 Feb 15;66(3):726-39. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17143896 17143896]
</div>
<div class="pdbe-citations 1rfl" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
[[Category: Single protein]]
[[Category: Large Structures]]
[[Category: Armengod, M.E.]]
[[Category: Armengod ME]]
[[Category: Celda, B.]]
[[Category: Celda B]]
[[Category: Esteve, V.]]
[[Category: Esteve V]]
[[Category: Martinez-Vicente, M.]]
[[Category: Martinez-Vicente M]]
[[Category: Monleon, D.]]
[[Category: Monleon D]]
[[Category: Yim, L.]]
[[Category: Yim L]]
[[Category: alpha/beta]]
[[Category: gtpase domain]]
 
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