3fi1

<table><tr><td colspan='2'>[[3fi1]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_k-12 Escherichia coli k-12]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3FI1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3FI1 FirstGlance]. <br>

</td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3fi1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3fi1 OCA], [https://pdbe.org/3fi1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3fi1 RCSB], [https://www.ebi.ac.uk/pdbsum/3fi1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3fi1 ProSAT]</span></td></tr>

[[https://www.uniprot.org/uniprot/NHAA_ECOLI NHAA_ECOLI]] Na(+)/H(+) antiporter that extrudes sodium in exchange for external protons. Catalyzes the exchange of 2 H(+) per Na(+). Can mediate sodium uptake when a transmembrane pH gradient is applied. Active at alkaline pH. Activity is strongly down-regulated below pH 6.5.<ref>PMID:1645730</ref>

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== Publication Abstract from PubMed ==

NhaA, the main sodium-proton exchanger in the inner membrane of Escherichia coli, regulates the cytosolic concentrations of H and Na. It is inactive at acidic pH, becomes active between pH 6 and pH 7, and reaches maximum activity at pH 8. By cryo-electron microscopy of two-dimensional crystals grown at pH 4 and incubated at higher pH, we identified two sequential conformational changes in the protein in response to pH or substrate ions. The first change is induced by a rise in pH from 6 to 7 and marks the transition from the inactive state to the pH-activated state. pH activation, which precedes the ion-induced conformational change, is accompanied by an overall expansion of the NhaA monomer and a local ordering of the N-terminus. The second conformational change is induced by the substrate ions Na and Li at pH above 7 and involves a 7-A displacement of helix IVp. This movement would cause a charge imbalance at the ion-binding site that may trigger the release of the substrate ion and open a periplasmic exit channel.

Conformations of NhaA, the Na/H exchanger from Escherichia coli, in the pH-activated and ion-translocating states.,Appel M, Hizlan D, Vinothkumar KR, Ziegler C, Kuhlbrandt W J Mol Biol. 2009 Feb 20;386(2):351-65. Epub 2008 Dec 25. PMID:19135453<ref>PMID:19135453</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 3fi1" style="background-color:#fffaf0;"></div>

[[Category: Escherichia coli k-12]]

[[Category: Appel, M]]

[[Category: Hizlan, D]]

[[Category: Kuehlbrandt, W]]

[[Category: Vinothkumar, K R]]

[[Category: Ziegler, C]]

[[Category: Transport]]