View source for 1b8o


==PURINE NUCLEOSIDE PHOSPHORYLASE==
<StructureSection load='1b8o' size='340' side='right'caption='[[1b8o]], [[Resolution|resolution]] 1.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1b8o]] 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=1B8O OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1B8O 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]] 1.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=IMH:1,4-DIDEOXY-4-AZA-1-(S)-(9-DEAZAHYPOXANTHIN-9-YL)-D-RIBITOL'>IMH</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</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=1b8o FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1b8o OCA], [https://pdbe.org/1b8o PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1b8o RCSB], [https://www.ebi.ac.uk/pdbsum/1b8o PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1b8o ProSAT]</span></td></tr>
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== 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/b8/1b8o_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=1b8o ConSurf].
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== Publication Abstract from PubMed ==
Immucillin-H [ImmH; (1S)-1-(9-deazahypoxanthin-9-yl)-1,4-dideoxy-1,4-imino-D-ribitol] is a 23 pM inhibitor of bovine purine nucleoside phosphorylase (PNP) specifically designed as a transition state mimic [Miles, R. W., Tyler, P. C., Furneaux, R. H., Bagdassarian, C. K., and Schramm, V. L. (1998) Biochemistry 37, 8615-8621]. Cocrystals of PNP and the inhibitor are used to provide structural information for each step through the reaction coordinate of PNP. The X-ray crystal structure of free ImmH was solved at 0.9 A resolution, and a complex of PNP.ImmH.PO(4) was solved at 1.5 A resolution. These structures are compared to previously reported complexes of PNP with substrate and product analogues in the catalytic sites and with the experimentally determined transition state structure. Upon binding, ImmH is distorted to a conformation favoring ribosyl oxocarbenium ion formation. Ribosyl destabilization and transition state stabilization of the ribosyl oxocarbenium ion occur from neighboring group interactions with the phosphate anion and the 5'-hydroxyl of the ribosyl group. Leaving group activation of hypoxanthine involves hydrogen bonds to O6, N1, and N7 of the purine ring. Ordered water molecules provide a proton transfer bridge to O6 and N7 and permit reversible formation of these hydrogen bonds. Contacts between PNP and catalytic site ligands are shorter in the transition state analogue complex of PNP.ImmH.PO(4) than in the Michaelis complexes of PNP.inosine.SO(4) or PNP.hypoxanthine.ribose 1-PO(4). Reaction coordinate motion is dominated by translation of the carbon 1' of ribose between relatively fixed phosphate and purine groups. Purine and pyrimidine phosphoribosyltransferases and nucleoside N-ribosyl hydrolases appear to operate by a similar mechanism.

Transition state structure of purine nucleoside phosphorylase and principles of atomic motion in enzymatic catalysis.,Fedorov A, Shi W, Kicska G, Fedorov E, Tyler PC, Furneaux RH, Hanson JC, Gainsford GJ, Larese JZ, Schramm VL, Almo SC Biochemistry. 2001 Jan 30;40(4):853-60. PMID:11170405<ref>PMID:11170405</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: Almo SC]]
[[Category: Fedorov AA]]
[[Category: Fedorov EV]]
[[Category: Furneaux RH]]
[[Category: Kicska GA]]
[[Category: Schramm VL]]
[[Category: Shi W]]
[[Category: Tyler PC]]