View source for 1szk


==The structure of gamma-aminobutyrate aminotransferase mutant: E211S==
<StructureSection load='1szk' size='340' side='right'caption='[[1szk]], [[Resolution|resolution]] 2.52&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1szk]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SZK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1SZK FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.52&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=PMP:4-DEOXY-4-AMINOPYRIDOXAL-5-PHOSPHATE'>PMP</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></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=1szk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1szk OCA], [https://pdbe.org/1szk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1szk RCSB], [https://www.ebi.ac.uk/pdbsum/1szk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1szk ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/GABT_ECOLI GABT_ECOLI] Catalyzes the transfer of the amino group from gamma-aminobutyrate (GABA) to alpha-ketoglutarate (KG) to yield succinic semialdehyde (SSA).<ref>PMID:20639325</ref> 
== 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/sz/1szk_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/main_output.php?pdb_ID=1szk ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The E. coli isozyme of gamma-aminobutyrate aminotransferase (GABA-AT) is a tetrameric pyridoxal phosphate-dependent enzyme that catalyzes transamination between primary amines and alpha-keto acids. The roles of the active site residues V241, E211, and I50 in the GABA-AT mechanism have been probed by site-directed mutagenesis. The beta-branched side chain of V241 facilitates formation of external aldimine intermediates with primary amine substrates, while E211 provides charge compensation of R398 selectively in the primary amine half-reaction and I50 forms a hydrophobic lid at the top of the substrate binding site. The structures of the I50Q, V241A, and E211S mutants were solved by X-ray crystallography to resolutions of 2.1, 2.5, and 2.52 A, respectively. The structure of GABA-AT is similar in overall fold and active site structure to that of dialkylglycine decarboxylase, which catalyzes both transamination and decarboxylation half-reactions in its normal catalytic cycle. Therefore, an attempt was made to convert GABA-AT into a decarboxylation-dependent aminotransferase similar to dialkylglycine decarboxylase by systematic mutation of E. coli GABA-AT active site residues. Two of the twelve mutants presented, E211S/I50G/C77K and E211S/I50H/V80D, have approximately 10-fold higher decarboxylation activities than the wild-type enzyme, and the E211S/I50H/V80D has formally changed the reaction specificity to that of a decarboxylase.

Kinetic and crystallographic analysis of active site mutants of Escherichia coli gamma-aminobutyrate aminotransferase.,Liu W, Peterson PE, Langston JA, Jin X, Zhou X, Fisher AJ, Toney MD Biochemistry. 2005 Mar 1;44(8):2982-92. PMID:15723541<ref>PMID:15723541</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 1szk" style="background-color:#fffaf0;"></div>

==See Also==
*[[Aminotransferase 3D structures|Aminotransferase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Fisher AJ]]
[[Category: Jin X]]
[[Category: Langston JA]]
[[Category: Liu W]]
[[Category: Peterson PE]]
[[Category: Toney MD]]