1nul: Difference between revisions

New page: left|200px<br /><applet load="1nul" size="450" color="white" frame="true" align="right" spinBox="true" caption="1nul, resolution 1.80Å" /> '''XPRTASE FROM E. COLI...
 
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[[Image:1nul.gif|left|200px]]<br /><applet load="1nul" size="450" color="white" frame="true" align="right" spinBox="true"
caption="1nul, resolution 1.80&Aring;" />
'''XPRTASE FROM E. COLI'''<br />


==Overview==
==XPRTASE FROM E. COLI==
Xanthine phosphoribosyltransferase (XPRT; EC 2.4.2.22) from Escherichia, coli is a tetrameric enzyme having 152 residues per subunit. XPRT, catalyzes the transfer of the phosphoribosyl group from, 5-phospho-alpha-D-ribosyl 1-pyrophosphate (PRib-PP) to the 6-oxopurine, bases guanine, xanthine, and hypoxanthine to form GMP, XMP, and IMP, respectively. Crystals grown in the absence of substrate or product were, used to determine the structure of XPRT at a resolution of 1.8 A, by, multiple isomorphous replacement. The core structure of XPRT includes a, five-stranded parallel beta-sheet surrounded by three alpha-helices, which, is similar to that observed in other known phosphoribosyltransferase, (PRTase) structures. The XPRT structure also has several interesting, features. A glutamine residue in the purine binding site may be, responsible for the altered 6-oxopurine base specificity seen in this, enzyme compared to other 6-oxopurine PRTases. Also, we observe both a, magnesium ion and a sulfate ion bound at the PRib-PP binding site of XPRT., The sulfate ion interacts with Arg-37 which has a cis-peptide, conformation, and the magnesium ion interacts with Asp-89, a highly, conserved acidic residue in the PRib-PP binding site motif. The XPRT, structure also incorporates a feature which has not been observed in other, PRTase structures. The C-terminal 12 residues of XPRT adopt an unusual, extended conformation and make interactions with a neighboring subunit., The very last residue, Arg-152, could form part of the active site of a, symmetry-related subunit in the XPRT tetramer.
<StructureSection load='1nul' size='340' side='right'caption='[[1nul]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1nul]] is a 2 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=1NUL OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1NUL 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]] 1.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</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=1nul FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1nul OCA], [https://pdbe.org/1nul PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1nul RCSB], [https://www.ebi.ac.uk/pdbsum/1nul PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1nul ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/XGPT_ECOLI XGPT_ECOLI] Acts on guanine, xanthine and to a lesser extent hypoxanthine.<ref>PMID:9100006</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/nu/1nul_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=1nul ConSurf].
<div style="clear:both"></div>


==About this Structure==
==See Also==
1NUL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with SO4 and MG as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Xanthine_phosphoribosyltransferase Xanthine phosphoribosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.2.22 2.4.2.22] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1NUL OCA].
*[[Phosphoribosyltransferase 3D structures|Phosphoribosyltransferase 3D structures]]
 
== References ==
==Reference==
<references/>
Crystal structure of Escherichia coli xanthine phosphoribosyltransferase., Vos S, de Jersey J, Martin JL, Biochemistry. 1997 Apr 8;36(14):4125-34. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9100006 9100006]
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
[[Category: Single protein]]
[[Category: Large Structures]]
[[Category: Xanthine phosphoribosyltransferase]]
[[Category: De Jersey J]]
[[Category: Jersey, J.De.]]
[[Category: Martin JL]]
[[Category: Martin, J.L.]]
[[Category: Vos S]]
[[Category: Vos, S.]]
[[Category: MG]]
[[Category: SO4]]
[[Category: phosphoribosyltransferase]]
[[Category: purine salvage enzyme]]
[[Category: transferase]]
 
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