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2gja

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[[Image:2gja.gif|left|200px]]
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{{STRUCTURE_2gja| PDB=2gja | SCENE= }}
{{STRUCTURE_2gja| PDB=2gja | SCENE= }}
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'''Structure of the MnmE G-domain in complex with GDP*AlF4-, Mg2+ and NH4+'''
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===Structure of the MnmE G-domain in complex with GDP*AlF4-, Mg2+ and NH4+===
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==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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The line below this paragraph, {{ABSTRACT_PUBMED_16763562}}, adds the Publication Abstract to the page
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(as it appears on PubMed at http://www.pubmed.gov), where 16763562 is the PubMed ID number.
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{{ABSTRACT_PUBMED_16763562}}
==About this Structure==
==About this Structure==
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[[Category: Alpha-beta-sandwich]]
[[Category: Alpha-beta-sandwich]]
[[Category: G-domain dimer]]
[[Category: G-domain dimer]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 05:10:18 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Jul 27 20:32:52 2008''

Revision as of 17:33, 27 July 2008

Template:STRUCTURE 2gja

Structure of the MnmE G-domain in complex with GDP*AlF4-, Mg2+ and NH4+

Template:ABSTRACT PUBMED 16763562

About this Structure

2GJA is a Single protein structure of sequence from Escherichia coli. 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 Sun Jul 27 20:32:52 2008

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