View source for 1a9r


==BOVINE PURINE NUCLEOSIDE PHOSPHORYLASE COMPLEXED WITH HYPOXANTHINE AND SULFATE==
<StructureSection load='1a9r' size='340' side='right'caption='[[1a9r]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1a9r]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Bos_taurus Bos taurus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A9R OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1A9R FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HPA:HYPOXANTHINE'>HPA</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Purine-nucleoside_phosphorylase Purine-nucleoside phosphorylase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.2.1 2.4.2.1] </span></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=1a9r FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1a9r OCA], [https://pdbe.org/1a9r PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1a9r RCSB], [https://www.ebi.ac.uk/pdbsum/1a9r PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1a9r ProSAT]</span></td></tr>
</table>
== Function ==
[[https://www.uniprot.org/uniprot/PNPH_BOVIN PNPH_BOVIN]] The purine nucleoside phosphorylases catalyze the phosphorolytic breakdown of the N-glycosidic bond in the beta-(deoxy)ribonucleoside molecules, with the formation of the corresponding free purine bases and pentose-1-phosphate. 
== 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/a9/1a9r_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=1a9r ConSurf].
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== Publication Abstract from PubMed ==
Purine nucleoside phosphorylase (PNP) is a key enzyme in the purine salvage pathway, which provides an alternative to the de novo pathway for the biosynthesis of purine nucleotides. PNP catalyzes the reversible phosphorolysis of 2'-deoxypurine ribonucleosides to the free bases and 2-deoxyribose 1-phosphate. Absence of PNP activity in humans is associated with specific T-cell immune suppression. Its key role in these two processes has made PNP an important drug design target. We have investigated the structural details of the PNP-catalyzed reaction by determining the structures of bovine PNP complexes with various substrates and substrate analogues. The preparation of phosphate-free crystals of PNP has allowed us to analyze several novel complexes, including the ternary complex of PNP, purine base, and ribose 1-phosphate and of the completely unbound PNP. These results provide an atomic view for the catalytic mechanism for PNP proposed by M. D. Erion et al. [(1997) Biochemistry 36, 11735-11748], in which an oxocarbenium intermediate is stabilized by phosphate and the negative charge on the purine base is stabilized by active site residues. The bovine PNP structure reveals several new details of substrate and inhibitor binding, including two phosphate-induced conformational changes involving residues 33-36 and 56-69 and a previously undetected role for His64 in phosphate binding. In addition, a well-ordered water molecule is found in the PNP active site when purine base or nucleoside is also present. In contrast to human PNP, only one phosphate binding site was observed. Although binary complexes were observed for nucleoside, purine base, or phosphate, ribose 1-phosphate binding occurs only in the presence of purine base.

Calf spleen purine nucleoside phosphorylase complexed with substrates and substrate analogues.,Mao C, Cook WJ, Zhou M, Federov AA, Almo SC, Ealick SE Biochemistry. 1998 May 19;37(20):7135-46. PMID:9585525<ref>PMID:9585525</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Purine nucleoside phosphorylase 3D structures|Purine nucleoside phosphorylase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bos taurus]]
[[Category: Large Structures]]
[[Category: Purine-nucleoside phosphorylase]]
[[Category: Almo, S C]]
[[Category: Cook, W J]]
[[Category: Ealick, S E]]
[[Category: Fedorov, A A]]
[[Category: Mao, C]]
[[Category: Zhou, M]]
[[Category: Pentosyltransferase]]
[[Category: Purine nucleoside phosphorylase]]