2dgl: Difference between revisions
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New page: left|200px<br /><applet load="2dgl" size="450" color="white" frame="true" align="right" spinBox="true" caption="2dgl, resolution 3.15Å" /> '''Crystal structure of... |
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[[Image:2dgl.gif|left|200px]]<br /><applet load="2dgl" size=" | [[Image:2dgl.gif|left|200px]]<br /><applet load="2dgl" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="2dgl, resolution 3.15Å" /> | caption="2dgl, resolution 3.15Å" /> | ||
'''Crystal structure of Escherichia coli GadB in complex with bromide'''<br /> | '''Crystal structure of Escherichia coli GadB in complex with bromide'''<br /> | ||
==Overview== | ==Overview== | ||
Escherichia coli and other enterobacteria exploit the H+ -consuming | Escherichia coli and other enterobacteria exploit the H+ -consuming reaction catalysed by glutamate decarboxylase to survive the stomach acidity before reaching the intestine. Here we show that chloride, extremely abundant in gastric secretions, is an allosteric activator producing a 10-fold increase in the decarboxylase activity at pH 5.6. Cooperativity and sensitivity to chloride were lost when the N-terminal 14 residues, involved in the formation of two triple-helix bundles, were deleted by mutagenesis. X-ray structures, obtained in the presence of the substrate analogue acetate, identified halide-binding sites at the base of each N-terminal helix, showed how halide binding is responsible for bundle stability and demonstrated that the interconversion between active and inactive forms of the enzyme is a stepwise process. We also discovered an entirely novel structure of the cofactor pyridoxal 5'-phosphate (aldamine) to be responsible for the reversibly inactivated enzyme. Our results link the entry of chloride ions, via the H+/Cl- exchange activities of ClC-ec1, to the trigger of the acid stress response in the cell when the intracellular proton concentration has not yet reached fatal values. | ||
==About this Structure== | ==About this Structure== | ||
2DGL 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 BR, PLP and ACY as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Glutamate_decarboxylase Glutamate decarboxylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.1.1.15 4.1.1.15] Full crystallographic information is available from [http:// | 2DGL 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=BR:'>BR</scene>, <scene name='pdbligand=PLP:'>PLP</scene> and <scene name='pdbligand=ACY:'>ACY</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Glutamate_decarboxylase Glutamate decarboxylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.1.1.15 4.1.1.15] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2DGL OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Capitani, G.]] | [[Category: Capitani, G.]] | ||
[[Category: Gruetter, M | [[Category: Gruetter, M G.]] | ||
[[Category: Gut, H.]] | [[Category: Gut, H.]] | ||
[[Category: ACY]] | [[Category: ACY]] | ||
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[[Category: gadb complexed with bromide]] | [[Category: gadb complexed with bromide]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:58:33 2008'' | ||
