1xrj

<table><tr><td colspan='2'>[[1xrj]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XRJ OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=1XRJ FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ADP:ADENOSINE-5-DIPHOSPHATE'>ADP</scene>, <scene name='pdbligand=C5P:CYTIDINE-5-MONOPHOSPHATE'>C5P</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1udw|1udw]], [[1uei|1uei]], [[1uej|1uej]], [[1ufq|1ufq]], [[1uj2|1uj2]]</div></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">UCK2, UMPK ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Uridine_kinase Uridine kinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.1.48 2.7.1.48] </span></td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=1xrj FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xrj OCA], [http://pdbe.org/1xrj PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1xrj RCSB], [http://www.ebi.ac.uk/pdbsum/1xrj PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1xrj ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/UCK2_HUMAN UCK2_HUMAN]] Phosphorylates uridine and cytidine to uridine monophosphate and cytidine monophosphate. Does not phosphorylate deoxyribonucleosides or purine ribonucleosides. Can use ATP or GTP as a phosphate donor. Can also phosphorylate cytidine and uridine nucleoside analogs such as 6-azauridine, 5-fluorouridine, 4-thiouridine, 5-bromouridine, N(4)-acetylcytidine, N(4)-benzoylcytidine, 5-fluorocytidine, 2-thiocytidine, 5-methylcytidine, and N(4)-anisoylcytidine.

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== Publication Abstract from PubMed ==

Uridine-cytidine nucleoside kinase 2 (UCK2) is the rate-limiting enzyme in the pyrimidine-nucleotide salvage pathway. UCK2 catalyzes the phosphorylation of the natural ribonucleosides cytidine and uridine to cytidine 5'-monophosphate (CMP) and uridine 5'-monophosphate (UMP), respectively, and activates several important frontline antimetabolite drugs. The present contribution reports the rapid crystal structure determination of human UCK2 complexed with a magnesium ion and the reaction products adenosine 5'-diphosphate (ADP) and CMP. Diffraction data were collected on a copper rotating-anode X-ray generator from one native UCK2 crystal and a single samarium-derivative crystal. Utilizing the relatively high anomalous signal from the samarium derivative at the Cu Kalpha wavelength, the structure was determined by single isomorphous replacement and single anomalous signal (SIRAS) phasing techniques. Two of the four major samarium sites are located in the active sites of the two UCK2 molecules that form the asymmetric unit and appear to displace the magnesium ions present in the native crystals. The crystal structures of UCK2 alone and in complex with various ligands have recently been determined using traditional multiple isomorphous replacement (MIR) phasing techniques and data from three heavy-atom derivatives. The reported structures validate our independently determined structure. Of more than 1000 kinase crystal structure entries in the Protein Data Bank, less than 1% of them have been determined by SIRAS. For the published kinase crystal structures determined by SIRAS, all data were reportedly collected at various synchrotron-radiation facilities. This study demonstrates that diffraction data collected from a single samarium derivative using Cu Kalpha radiation provides sufficient phasing power to determine a novel macromolecular crystal structure.

Structure of human uridine-cytidine kinase 2 determined by SIRAS using a rotating-anode X-ray generator and a single samarium derivative.,Appleby TC, Larson G, Cheney IW, Walker H, Wu JZ, Zhong W, Hong Z, Yao N Acta Crystallogr D Biol Crystallogr. 2005 Mar;61(Pt 3):278-84. Epub 2005, Feb 24. PMID:15735337<ref>PMID:15735337</ref>

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

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== References ==

<references/>

[[Category: Human]]

[[Category: Appleby, T C]]

[[Category: Cheney, I W]]

[[Category: Hong, Z]]

[[Category: Larson, G]]

[[Category: Wu, J Z]]

[[Category: Yao, N]]

[[Category: Uridine-cytidine kinase]]