This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
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...) |
|||
| Line 1: | Line 1: | ||
| - | [[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== | ||
| Line 22: | Line 22: | ||
[[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
|
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
Page seeded by OCA on Thu Feb 21 16:14:10 2008
