View source for 2fxv

==Bacillus subtilis Xanthine Phosphoribosyltransferase in Complex with Guanosine 5'-monophosphate (GMP)==
<StructureSection load='2fxv' size='340' side='right' caption='[[2fxv]], [[Resolution|resolution]] 2.05&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2fxv]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_globigii"_migula_1900 "bacillus globigii" migula 1900]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2FXV OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2FXV FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=5GP:GUANOSINE-5-MONOPHOSPHATE'>5GP</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene></td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">xpt ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1423 "Bacillus globigii" Migula 1900])</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[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] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2fxv FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2fxv OCA], [http://pdbe.org/2fxv PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2fxv RCSB], [http://www.ebi.ac.uk/pdbsum/2fxv PDBsum]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/XPT_BACSU XPT_BACSU]] Converts the preformed base xanthine, a product of nucleic acid breakdown, to xanthosine 5'-monophosphate (XMP), so that it can be reused for RNA or DNA synthesis.[HAMAP-Rule:MF_01184] 
== 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/fx/2fxv_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=2fxv ConSurf].
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== Publication Abstract from PubMed ==
Xanthine phosphoribosyltransferase (XPRTase) from Bacillus subtilis is a representative of the highly xanthine specific XPRTases found in Gram-positive bacteria. These XPRTases constitute a distinct subclass of 6-oxopurine PRTases, which deviate strongly from the major class of H(X)GPRTases with respect to sequence, PRPP binding motif, and oligomeric structure. They are more related with the PurR repressor of Gram-positive bacteria, the adenine PRTase, and orotate PRTase. The catalytic function and high specificity for xanthine of B. subtilis XPRTase were investigated by ligand binding studies and reaction kinetics as a function of pH with xanthine, hypoxanthine, and guanine as substrates. The crystal structure of the dimeric XPRTase-GMP complex was determined to 2.05 A resolution. In a sequential reaction mechanism XPRTase binds first PRPP, stabilizing its active dimeric form, and subsequently xanthine. The XPRTase is able also to react with guanine and hypoxanthine albeit at much lower (10(-)(4)-fold) catalytic efficiency. Different pK(a) values for the bases and variations in their electrostatic potential can account for these catalytic differences. The unique base specificity of XPRTase has been related to a few key residues in the active site. Asn27 can in different orientations form hydrogen bonds to an amino group or an oxo group at the 2-position of the purine base, and Lys156 is positioned to make a hydrogen bond with N7. This and the absence of a catalytic carboxylate group near the N7-position require the purine base to dissociate a proton spontaneously in order to undergo catalysis.

The extraordinary specificity of xanthine phosphoribosyltransferase from Bacillus subtilis elucidated by reaction kinetics, ligand binding, and crystallography.,Arent S, Kadziola A, Larsen S, Neuhard J, Jensen KF Biochemistry. 2006 May 30;45(21):6615-27. PMID:16716072<ref>PMID:16716072</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 2fxv" style="background-color:#fffaf0;"></div>

==See Also==
*[[Phosphoribosyltransferase|Phosphoribosyltransferase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bacillus globigii migula 1900]]
[[Category: Xanthine phosphoribosyltransferase]]
[[Category: Arent, S]]
[[Category: Jensen, K F]]
[[Category: Kadziola, A]]
[[Category: Larsen, S]]
[[Category: Neuhard, J]]
[[Category: Gmp complex]]
[[Category: Transferase]]
[[Category: Type 1 phosphoribosyltransferase]]