2npe: Difference between revisions

Revision as of 09:44, 4 May 2008

An unusual twin-His arrangement in the pore of ammonia channels is essential for substrate conductance

OverviewOverview

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.

About this StructureAbout this Structure

2NPE is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.

ReferenceReference

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 Page seeded by OCA on Sun May 4 09:44:31 2008

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

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 [[Image:2npe.gif|left|200px]]
- {{Structure
+<!--
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+The line below this paragraph, containing "STRUCTURE_2npe", creates the "Structure Box" on the page.
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-|GENE= amtB ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli])
+-->
-|DOMAIN=
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-|RELATEDENTRY=[[1xqf|1XQF]], [[1xqe|1XQE]], [[1u7g|1U7G]], [[2nmr|2NMR]], [[2nop|2NOP]], [[2now|2NOW]], [[2npc|2NPC]], [[2npd|2NPD]], [[2npg|2NPG]], [[2npj|2NPJ]], [[2npk|2NPK]]
-|RESOURCES=<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.ebi.ac.uk/pdbsum/2npe PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2npe RCSB]</span>
-}}
 '''An unusual twin-His arrangement in the pore of ammonia channels is essential for substrate conductance'''
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 [[Category: Lupo, D.]]
 [[Category: Winkler, F K.]]
-[[Category: ammonia transport]]
+[[Category: Ammonia transport]]
-[[Category: amtb]]
+[[Category: Amtb]]
-[[Category: histidine mutant]]
+[[Category: Histidine mutant]]
-[[Category: membrane protein]]
+[[Category: Membrane protein]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May  4 09:44:31 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 04:06:24 2008''