View source for 1sms


==Structure of the Ribonucleotide Reductase Rnr4 Homodimer from Saccharomyces cerevisiae==
<StructureSection load='1sms' size='340' side='right'caption='[[1sms]], [[Resolution|resolution]] 3.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1sms]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SMS OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1SMS 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]] 3.1&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HG:MERCURY+(II)+ION'>HG</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=1sms FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1sms OCA], [https://pdbe.org/1sms PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1sms RCSB], [https://www.ebi.ac.uk/pdbsum/1sms PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1sms ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/RIR4_YEAST RIR4_YEAST] Provides the precursors necessary for DNA synthesis. Catalyzes the biosynthesis of deoxyribonucleotides from the corresponding ribonucleotides. RNR4 is required for proper folding of RNR2 and assembly with the large subunits.<ref>PMID:10535923</ref> 
== 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/sm/1sms_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=1sms ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Class I ribonucleotide reductases (RNRs) catalyze the reduction of ribonucleotides to deoxyribonucleotides. Eukaryotic RNRs comprise two subunits, the R1 subunit, which contains substrate and allosteric effector binding sites, and the R2 subunit, which houses a catalytically essential diiron-tyrosyl radical cofactor. In Saccharomyces cerevisiae, there are two variants of the R2 subunit, called Rnr2 and Rnr4. Rnr4 is unique in that it lacks three iron-binding residues conserved in all other R2s. Nevertheless, Rnr4 is required to activate Rnr2, and the functional species in vivo is believed to be a heterodimeric complex between the two proteins. The crystal structures of the Rnr2 and Rnr4 homodimers have been determined and are compared to that of the heterodimer. The homodimers are very similar to the heterodimer and to mouse R2 in overall fold, but there are several key differences. In the Rnr2 homodimer, one of the iron-binding helices, helix alphaB, is not well-ordered. In the heterodimer, interactions with a loop region connecting Rnr4 helices alphaA and alpha3 stabilize this Rnr2 helix, which donates iron ligand Asp 145. Sequence differences between Rnr2 and Rnr4 prevent the same interactions from occurring in the Rnr2 homodimer. These findings provide a structural rationale for why the heterodimer is the preferred complex in vivo. The active-site region in the Rnr4 homodimer reveals interactions not apparent in the heterodimer, supporting previous conclusions that this subunit does not bind iron. When taken together, these results support a model in which Rnr4 stabilizes Rnr2 for cofactor assembly and activity.

Structures of the yeast ribonucleotide reductase Rnr2 and Rnr4 homodimers.,Sommerhalter M, Voegtli WC, Perlstein DL, Ge J, Stubbe J, Rosenzweig AC Biochemistry. 2004 Jun 22;43(24):7736-42. PMID:15196016<ref>PMID:15196016</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 1sms" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ribonucleotide reductase 3D structures|Ribonucleotide reductase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Saccharomyces cerevisiae]]
[[Category: Ge J]]
[[Category: Perlstein DL]]
[[Category: Rosenzweig AC]]
[[Category: Sommerhalter M]]
[[Category: Stubbe J]]
[[Category: Voegtli WC]]