View source for 3t8i


==Structural analysis of thermostable S. solfataricus purine-specific nucleoside hydrolase==
<StructureSection load='3t8i' size='340' side='right'caption='[[3t8i]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3t8i]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Saccharolobus_solfataricus_P2 Saccharolobus solfataricus P2]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3T8I OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3T8I 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=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=PEG:DI(HYDROXYETHYL)ETHER'>PEG</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=3t8i FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3t8i OCA], [https://pdbe.org/3t8i PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3t8i RCSB], [https://www.ebi.ac.uk/pdbsum/3t8i PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3t8i ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q97WH6_SACS2 Q97WH6_SACS2] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The purine and pyrimidine-specific nucleoside hydrolases (NHs) from the archaeon Sulfolobus solfataricus participate in the fundamental pathway of nucleotide catabolism, and concur in maintaining adequate levels of free nitrogenous bases for cellular function. The two highly homologous isozymes display distinct specificities towards nucleoside substrates, and both lack the amino acids employed for activation of the leaving group in the hydrolytic reaction by the so far characterized NHs. We determined the high-resolution crystal structures of the purine and pyrimidine-specific NHs from S. solfataricus to reveal that both enzymes belong to the NH structural homology group I, despite the different substrate specificities. A Na+ ion is bound at the active site of the pyrimidine-specific NH instead of the prototypical Ca2+, delineating a role of the metals in the catalytic mechanism of NHs in the substrate binding rather than nucleophile activation. A conserved His residue, that regulates product release in other homologous NHs, provides crucial interactions for leaving group activation in the archaeal isozymes. Modeling of the enzyme-substrate interactions suggests that steric exclusion and catalytic selection underlie the orthogonal base specificity of the two isozymes.

New determinants in the catalytic mechanism of nucleoside hydrolases from the structures of two isozymes from Sulfolobus solfataricus.,Minici C, Cacciapuoti G, De Leo E, Porcelli M, Degano M Biochemistry. 2012 May 2. PMID:22551416<ref>PMID:22551416</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3t8i" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Saccharolobus solfataricus P2]]
[[Category: Cacciapuoti G]]
[[Category: De Leo E]]
[[Category: Degano M]]
[[Category: Minici C]]
[[Category: Porcelli M]]