2agk

<table><tr><td colspan='2'>[[2agk]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Atcc_18824 Atcc 18824]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2AGK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2AGK FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CIT:CITRIC+ACID'>CIT</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">YIL020c ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=4932 ATCC 18824])</td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/1-(5-phosphoribosyl)-5-_((5-phosphoribosylamino)methylideneamino)imidazole-4-carboxamide_isomerase 1-(5-phosphoribosyl)-5- ((5-phosphoribosylamino)methylideneamino)imidazole-4-carboxamide isomerase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.1.16 5.3.1.16] </span></td></tr>

[[https://www.uniprot.org/uniprot/HIS4_YEAST HIS4_YEAST]] Catalyzes the isomerization of the aminoaldose moiety of ProFAR to the aminoketose of PRFAR.

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== Publication Abstract from PubMed ==

The Saccharomyces cerevisiae His6 gene codes for the enzyme phosphoribosyl-5-amino-1-phosphoribosyl-4-imidazolecarboxamide isomerase, catalyzing the fourth step in histidine biosynthesis. To get an insight into the structure and function of this enzyme, we determined its X-ray structure at a resolution of 1.30 A using the anomalous diffraction signal of the protein's sulphur atoms at 1.77 A wavelength. His6 folds in an (alpha/beta)8 barrel similar to HisA, which performs the same function in bacteria and archaea. We found a citrate molecule from the buffer bound in a pocket near the expected position of the active site and used it to model the open form of the substrate (phosphoribulosyl moiety), which is a reaction intermediate. This model enables us to identify catalytic residues and to propose a reaction mechanism where two aspartates act as acid/base catalysts: Asp134 as a proton donor for ring opening, and Asp9 as a proton acceptor and donor during enolization of the aminoaldose. Asp9 is conserved in yeast His6 and bacterial or archaeal HisA sequences, and Asp134 has equivalents in both HisA and TrpF, but they occur at a different position in the protein sequence.

Crystal structure of the yeast His6 enzyme suggests a reaction mechanism.,Quevillon-Cheruel S, Leulliot N, Graille M, Blondeau K, Janin J, van Tilbeurgh H Protein Sci. 2006 Jun;15(6):1516-21. PMID:16731983<ref>PMID:16731983</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 2agk" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Atcc 18824]]

[[Category: Tilbeurgh, H V]]

[[Category: Structural genomic]]

[[Category: Ysg]]