1zcd: Difference between revisions

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[[Image:1zcd.gif|left|200px]]<br /><applet load="1zcd" size="~~450~~" color="white" frame="true" align="right" spinBox="true"

[[Image:1zcd.gif|left|200px]]<br /><applet load="1zcd" size="350" color="white" frame="true" align="right" spinBox="true"

caption="1zcd, resolution 3.45Å" />

'''Crystal structure of the Na+/H+ antiporter NhaA'''<br />

==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.

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 [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://~~ispc~~.weizmann.ac.il/oca-bin/ocashort?id=1ZCD OCA].

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==

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[[Category: membrane protein]]

''Page seeded by [http://~~ispc~~.weizmann.ac.il/oca OCA ] on ~~Wed Nov~~ 21 07:22:~~56 2007~~''

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:14:10 2008''

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@@ Line 1: / Line 1: @@
-[[Image:1zcd.gif|left|200px]]<br /><applet load="1zcd" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1zcd.gif|left|200px]]<br /><applet load="1zcd" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1zcd, resolution 3.45&Aring;" />
 '''Crystal structure of the Na+/H+ antiporter NhaA'''<br />
 ==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.
+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==
-ZCD 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://ispc.weizmann.ac.il/oca-bin/ocashort?id=1ZCD OCA].
+ZCD 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==
@@ Line 22: / Line 22: @@
 [[Category: membrane protein]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 07:22:56 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:14:10 2008''