2gj8
From Proteopedia
(New page: 200px<br /><applet load="2gj8" size="450" color="white" frame="true" align="right" spinBox="true" caption="2gj8, resolution 1.70Å" /> '''Structure of the Mnm...) |
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| - | [[Image:2gj8.gif|left|200px]]<br /><applet load="2gj8" size=" | + | [[Image:2gj8.gif|left|200px]]<br /><applet load="2gj8" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2gj8, resolution 1.70Å" /> | caption="2gj8, resolution 1.70Å" /> | ||
'''Structure of the MnmE G-domain in complex with GDP*AlF4-, Mg2+ and K+'''<br /> | '''Structure of the MnmE G-domain in complex with GDP*AlF4-, Mg2+ and K+'''<br /> | ||
==Overview== | ==Overview== | ||
| - | MnmE, a Guanine nucleotide-binding protein conserved between bacteria and | + | 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== | ||
| - | 2GJ8 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, K, SE and GDP as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 2GJ8 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=K:'>K</scene>, <scene name='pdbligand=SE:'>SE</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=2GJ8 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: g-domain dimer]] | [[Category: g-domain dimer]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:32:17 2008'' |
Revision as of 15:32, 21 February 2008
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Structure of the MnmE G-domain in complex with GDP*AlF4-, Mg2+ and K+
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
2GJ8 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
Page seeded by OCA on Thu Feb 21 17:32:17 2008
Categories: Escherichia coli | Single protein | Scrima, A. | Wittinghofer, A. | ALF | GDP | K | MG | SE | Alpha-beta-sandwich | G-domain dimer
