2gj9

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(New page: 200px<br /><applet load="2gj9" size="450" color="white" frame="true" align="right" spinBox="true" caption="2gj9, resolution 2.000&Aring;" /> '''Structure of the Mn...)
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[[Image:2gj9.gif|left|200px]]<br /><applet load="2gj9" size="450" color="white" frame="true" align="right" spinBox="true"
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[[Image:2gj9.gif|left|200px]]<br /><applet load="2gj9" size="350" color="white" frame="true" align="right" spinBox="true"
caption="2gj9, resolution 2.000&Aring;" />
caption="2gj9, resolution 2.000&Aring;" />
'''Structure of the MnmE G-domain in complex with GDP*AlF4-, Mg2+ and Rb+'''<br />
'''Structure of the MnmE G-domain in complex with GDP*AlF4-, Mg2+ and Rb+'''<br />
==Overview==
==Overview==
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MnmE, a Guanine nucleotide-binding protein conserved between bacteria and, man, is involved in the modification of tRNAs. Here we provide biochemical, and X-ray structural evidence for a new GTP-hydrolysis mechanism, where, the G-domains of MnmE dimerise in a potassium-dependent manner and induce, GTP hydrolysis. The structure in the presence of GDP-AlFx and potassium, shows how juxtaposition of the subunits induces a conformational change, around the nucleotide which reorients the catalytic machinery. A critical, glutamate is positioned such as to stabilise or activate the attacking, water. Potassium provides a positive charge into the catalytic site in a, position analogous to the arginine finger in the Ras-RasGAP system., Mutational studies show that potassium-dependent dimerisation and GTP, hydrolysis can be uncoupled and that interaction between the G-domains is, a prerequisite for subsequent phosphoryl transfer. We propose a model for, the juxtaposition of G-domains in the full-length protein and how it, induces conformational changes in the putative tRNA-modification centre.
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MnmE, a Guanine nucleotide-binding protein conserved between bacteria and man, is involved in the modification of tRNAs. Here we provide biochemical and X-ray structural evidence for a new GTP-hydrolysis mechanism, where the G-domains of MnmE dimerise in a potassium-dependent manner and induce GTP hydrolysis. The structure in the presence of GDP-AlFx and potassium shows how juxtaposition of the subunits induces a conformational change around the nucleotide which reorients the catalytic machinery. A critical glutamate is positioned such as to stabilise or activate the attacking water. Potassium provides a positive charge into the catalytic site in a position analogous to the arginine finger in the Ras-RasGAP system. Mutational studies show that potassium-dependent dimerisation and GTP hydrolysis can be uncoupled and that interaction between the G-domains is a prerequisite for subsequent phosphoryl transfer. We propose a model for the juxtaposition of G-domains in the full-length protein and how it induces conformational changes in the putative tRNA-modification centre.
==About this Structure==
==About this Structure==
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2GJ9 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with ALF, MG, RB and GDP as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2GJ9 OCA].
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2GJ9 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=ALF:'>ALF</scene>, <scene name='pdbligand=MG:'>MG</scene>, <scene name='pdbligand=RB:'>RB</scene> and <scene name='pdbligand=GDP:'>GDP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2GJ9 OCA].
==Reference==
==Reference==
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[[Category: g-domain dimer]]
[[Category: g-domain dimer]]
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''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 11:14:23 2007''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:32:13 2008''

Revision as of 15:32, 21 February 2008

Image:2gj9.gif

2gj9, resolution 2.000Å

Drag the structure with the mouse to rotate

Structure of the MnmE G-domain in complex with GDP*AlF4-, Mg2+ and Rb+

Overview

MnmE, a Guanine nucleotide-binding protein conserved between bacteria and man, is involved in the modification of tRNAs. Here we provide biochemical and X-ray structural evidence for a new GTP-hydrolysis mechanism, where the G-domains of MnmE dimerise in a potassium-dependent manner and induce GTP hydrolysis. The structure in the presence of GDP-AlFx and potassium shows how juxtaposition of the subunits induces a conformational change around the nucleotide which reorients the catalytic machinery. A critical glutamate is positioned such as to stabilise or activate the attacking water. Potassium provides a positive charge into the catalytic site in a position analogous to the arginine finger in the Ras-RasGAP system. Mutational studies show that potassium-dependent dimerisation and GTP hydrolysis can be uncoupled and that interaction between the G-domains is a prerequisite for subsequent phosphoryl transfer. We propose a model for the juxtaposition of G-domains in the full-length protein and how it induces conformational changes in the putative tRNA-modification centre.

About this Structure

2GJ9 is a Single protein structure of sequence from Escherichia coli with , , and as ligands. Full crystallographic information is available from OCA.

Reference

Dimerisation-dependent GTPase reaction of MnmE: how potassium acts as GTPase-activating element., Scrima A, Wittinghofer A, EMBO J. 2006 Jun 21;25(12):2940-51. Epub 2006 Jun 8. PMID:16763562

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