View source for 2npe

==An unusual twin-His arrangement in the pore of ammonia channels is essential for substrate conductance==
<StructureSection load='2npe' size='340' side='right' caption='[[2npe]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2npe]] is a 1 chain structure with 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=2NPE OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2NPE FirstGlance]. <br>
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene><br>
<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1xqf|1xqf]], [[1xqe|1xqe]], [[1u7g|1u7g]], [[2nmr|2nmr]], [[2nop|2nop]], [[2now|2now]], [[2npc|2npc]], [[2npd|2npd]], [[2npg|2npg]], [[2npj|2npj]], [[2npk|2npk]]</td></tr>
<tr><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">amtB ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli])</td></tr>
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2npe FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2npe OCA], [http://www.rcsb.org/pdb/explore.do?structureId=2npe RCSB], [http://www.ebi.ac.uk/pdbsum/2npe PDBsum]</span></td></tr>
<table>
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/np/2npe_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/chain_selection.php?pdb_ID=2ata ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Amt proteins constitute a class of ubiquitous integral membrane proteins that mediate movement of ammonium across cell membranes. They are homotrimers, in which each subunit contains a narrow pore through which substrate transport occurs. Two conserved histidine residues in the pore have been proposed to be necessary for ammonia conductance. By analyzing 14 engineered polar and non-polar variants of these histidines, in Escherichia coli AmtB, we show that both histidines are absolutely required for optimum substrate conductance. Crystal structures of variants confirm that substitution of the histidine residues does not affect AmtB structure. In a subgroup of Amt proteins, found only in fungi, one of the histidines is replaced by glutamate. The equivalent substitution in E. coli AmtB is partially active, and the structure of this variant suggests that the glutamate side chain can make similar interactions to those made by histidine.

An unusual twin-his arrangement in the pore of ammonia channels is essential for substrate conductance.,Javelle A, Lupo D, Zheng L, Li XD, Winkler FK, Merrick M J Biol Chem. 2006 Dec 22;281(51):39492-8. Epub 2006 Oct 12. PMID:17040913<ref>PMID:17040913</ref>

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

==See Also==
*[[Ion channels|Ion channels]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Lupo, D.]]
[[Category: Winkler, F K.]]
[[Category: Ammonia transport]]
[[Category: Amtb]]
[[Category: Histidine mutant]]
[[Category: Membrane protein]]
[[Category: Transport protein]]