1fxu

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GU7:2-AMINO-7-[2-(2-HYDROXY-1-HYDROXYMETHYL-ETHYLAMINO)-ETHYL]-1,7-DIHYDRO-PURIN-6-ONE'>GU7</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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>

[[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.

<div style="background-color:#fffaf0;">

== Publication Abstract from PubMed ==

The calf spleen purine nucleoside phosphorylase (PNP) ternary complex with an N(7)-acycloguanosine inhibitor and a phosphate ion has been crystallized in the cubic space group P2(1)3, with unit-cell parameter a = 94.11 A and one monomer per asymmetric unit. X-ray diffraction data were collected using synchrotron radiation (Station X31, EMBL Outstation, DESY, Hamburg). The crystal structure was refined to a resolution of 2.2 A and R and R(free) values of 17.5 and 24.5%, respectively. The acyclonucleoside inhibitor is bound in the active site in an inverted ('upside-down') orientation of the purine base compared with natural substrates. The side chain of Asp243 forms two hydrogen bonds with the base ring: N(delta) donates a hydrogen to N(3) and O(delta) accepts a hydrogen from the guanine N(2)-amino group. N(1)--H of the base is hydrogen bonded to O(epsilon) of Glu201, while N(9) accepts a hydrogen bond from Thr242 O(gamma). In addition, a water molecule (W417) bridges the N(2)-amino group of the base and O(epsilon) of Glu201. In the phosphate-binding site, a phosphate ion is bound to Ser33, His64, Arg84, His86, Ala116 and Ser220. The acyclic chain of the N(7)-acycloguanosine inhibitor is in a folded conformation and together with a water molecule (W388) occupies the pentose-binding site, with possible hydrogen bonds to Tyr88 O(eta) and His257 N(delta 1). This new binding mode fully accounts for the previously observed substrate properties of 7-beta-D-ribofuranosides of hypoxanthine and guanine. It also provides a new starting point for the design of inhibitors of PNP for therapeutic and other applications.

Calf spleen purine nucleoside phosphorylase: structure of its ternary complex with an N(7)-acycloguanosine inhibitor and a phosphate anion.,Luic M, Koellner G, Shugar D, Saenger W, Bzowska A Acta Crystallogr D Biol Crystallogr. 2001 Jan;57(Pt 1):30-6. PMID:11134924<ref>PMID:11134924</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

</div>

<div class="pdbe-citations 1fxu" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Bzowska, A]]

[[Category: Koellner, G]]

[[Category: Luic, M]]

[[Category: Saenger, W]]

[[Category: Shugar, D]]

[[Category: Transferase]]