View source for 4gyn


==The E142L mutant of the amidase from Geobacillus pallidus==
<StructureSection load='4gyn' size='340' side='right'caption='[[4gyn]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4gyn]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_sp._(in:_Bacteria) Bacillus sp. (in: Bacteria)]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4GYN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4GYN 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]] 1.9&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</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=4gyn FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4gyn OCA], [https://pdbe.org/4gyn PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4gyn RCSB], [https://www.ebi.ac.uk/pdbsum/4gyn PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4gyn ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/AMIE_BACSP AMIE_BACSP] Catalyzes the hydrolysis of short-chain aliphatic amides to their corresponding organic acids with release of ammonia.<ref>PMID:10978771</ref>   Also exhibits in vitro acyl transferase activity, transferring the acyl moiety of short-chain amides to hydroxylamine to form hydroxamates (By similarity).<ref>PMID:10978771</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
All known nitrilase superfamily amidase and carbamoylase structures have an additional glutamate that is hydrogen bonded to the catalytic lysine in addition to the Glu, Lys, Cys "catalytic triad." In the amidase from Geobacillus pallidus, mutating this glutamate (Glu-142) to a leucine or aspartate renders the enzyme inactive. X-ray crystal structure determination shows that the structural integrity of the enzyme is maintained despite the mutation with the catalytic cysteine (Cys-166), lysine (Lys-134), and glutamate (Glu-59) in positions similar to those of the wild-type enzyme. In the case of the E142L mutant, a chloride ion is located in the position occupied by Glu-142 O(epsilon1) in the wild-type enzyme and interacts with the active site lysine. In the case of the E142D mutant, this site is occupied by Asp-142 O(delta1.) In neither case is an atom located at the position of Glu-142 O(epsilon2) in the wild-type enzyme. The active site cysteine of the E142L mutant was found to form a Michael adduct with acrylamide, which is a substrate of the wild-type enzyme, due to an interaction that places the double bond of the acrylamide rather than the amide carbonyl carbon adjacent to the active site cysteine. Our results demonstrate that in the wild-type active site a crucial role is played by the hydrogen bond between Glu-142 O(epsilon2) and the substrate amino group in positioning the substrate with the correct stereoelectronic alignment to enable the nucleophilic attack on the carbonyl carbon by the catalytic cysteine.

The mechanism of the amidases: mutating the glutamate adjacent to the catalytic triad inactivates the enzyme due to substrate mispositioning.,Weber BW, Kimani SW, Varsani A, Cowan DA, Hunter R, Venter GA, Gumbart JC, Sewell BT J Biol Chem. 2013 Oct 4;288(40):28514-23. doi: 10.1074/jbc.M113.503284. Epub 2013, Aug 14. PMID:23946488<ref>PMID:23946488</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4gyn" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Cowan DA]]
[[Category: Hunter R]]
[[Category: Kimani SW]]
[[Category: Sewell BT]]
[[Category: Varsani A]]
[[Category: Weber BW]]