1zcd
From Proteopedia
(New page: 200px<br /><applet load="1zcd" size="450" color="white" frame="true" align="right" spinBox="true" caption="1zcd, resolution 3.45Å" /> '''Crystal structure of...) |
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| - | [[Image:1zcd.gif|left|200px]]<br /><applet load="1zcd" size=" | + | [[Image:1zcd.gif|left|200px]]<br /><applet load="1zcd" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1zcd, resolution 3.45Å" /> | caption="1zcd, resolution 3.45Å" /> | ||
'''Crystal structure of the Na+/H+ antiporter NhaA'''<br /> | '''Crystal structure of the Na+/H+ antiporter NhaA'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The control by Na+/H+ antiporters of sodium/proton concentration and cell | + | The control by Na+/H+ antiporters of sodium/proton concentration and cell volume is crucial for the viability of all cells. Adaptation to high salinity and/or extreme pH in plants and bacteria or in human heart muscles requires the action of Na+/H+ antiporters. Their activity is tightly controlled by pH. Here we present the crystal structure of pH-downregulated NhaA, the main antiporter of Escherichia coli and many enterobacteria. A negatively charged ion funnel opens to the cytoplasm and ends in the middle of the membrane at the putative ion-binding site. There, a unique assembly of two pairs of short helices connected by crossed, extended chains creates a balanced electrostatic environment. We propose that the binding of charged substrates causes an electric imbalance, inducing movements, that permit a rapid alternating-access mechanism. This ion-exchange machinery is regulated by a conformational change elicited by a pH signal perceived at the entry to the cytoplasmic funnel. |
==About this Structure== | ==About this Structure== | ||
| - | 1ZCD 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:// | + | 1ZCD 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://oca.weizmann.ac.il/oca-bin/ocashort?id=1ZCD OCA]. |
==Reference== | ==Reference== | ||
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[[Category: membrane protein]] | [[Category: membrane protein]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:14:10 2008'' |
Revision as of 14:14, 21 February 2008
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Crystal structure of the Na+/H+ antiporter NhaA
Overview
The control by Na+/H+ antiporters of sodium/proton concentration and cell volume is crucial for the viability of all cells. Adaptation to high salinity and/or extreme pH in plants and bacteria or in human heart muscles requires the action of Na+/H+ antiporters. Their activity is tightly controlled by pH. Here we present the crystal structure of pH-downregulated NhaA, the main antiporter of Escherichia coli and many enterobacteria. A negatively charged ion funnel opens to the cytoplasm and ends in the middle of the membrane at the putative ion-binding site. There, a unique assembly of two pairs of short helices connected by crossed, extended chains creates a balanced electrostatic environment. We propose that the binding of charged substrates causes an electric imbalance, inducing movements, that permit a rapid alternating-access mechanism. This ion-exchange machinery is regulated by a conformational change elicited by a pH signal perceived at the entry to the cytoplasmic funnel.
About this Structure
1ZCD is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Structure of a Na+/H+ antiporter and insights into mechanism of action and regulation by pH., Hunte C, Screpanti E, Venturi M, Rimon A, Padan E, Michel H, Nature. 2005 Jun 30;435(7046):1197-202. PMID:15988517
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