View source for 1ou5


==Crystal structure of human CCA-adding enzyme==
<StructureSection load='1ou5' size='340' side='right'caption='[[1ou5]], [[Resolution|resolution]] 3.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ou5]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1OU5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1OU5 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]] 3.4&#8491;</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=1ou5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ou5 OCA], [https://pdbe.org/1ou5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ou5 RCSB], [https://www.ebi.ac.uk/pdbsum/1ou5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ou5 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/TRNT1_HUMAN TRNT1_HUMAN] Isoform 1: Adds and repairs the conserved 3'-CCA sequence necessary for the attachment of amino acids to the 3' terminus of tRNA molecules, using CTP and ATP as substrates.<ref>PMID:17204286</ref>   Isoform 2: Adds 2 C residues (CC-) to the 3' terminus of tRNA molecules instead of a complete CCA end as isoform 1 does (in vitro).<ref>PMID:17204286</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/ou/1ou5_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=1ou5 ConSurf].
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== Publication Abstract from PubMed ==
All tRNA molecules carry the invariant sequence CCA at their 3'-terminus for amino acid attachment. The post-transcriptional addition of CCA is carried out by ATP(CTP):tRNA nucleotidyltransferase, also called CCase. This enzyme catalyses a unique template-independent but sequence-specific nucleotide polymerization reaction. In order to reveal the molecular mechanism of this activity, we solved the crystal structure of human CCase by single isomorphous replacement. The structure reveals a four domain architecture with a cluster of conserved residues forming a positively charged cleft between the first two domains. Structural homology of the N-terminal CCase domain to other nucleotidyltransferases could be exploited for modeling a tRNA-substrate complex. The model places the tRNA 3'-end into the N-terminal nucleotidyltransferase site, close to a patch of conserved residues that provide the binding sites for CTP and ATP. Based on our results, we introduce a corkscrew model for CCA addition that includes a fixed active site and a traveling tRNA-binding region formed by flexible parts of the protein.

Crystal structure of the human CCA-adding enzyme: insights into template-independent polymerization.,Augustin MA, Reichert AS, Betat H, Huber R, Morl M, Steegborn C J Mol Biol. 2003 May 16;328(5):985-94. PMID:12729736<ref>PMID:12729736</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1ou5" style="background-color:#fffaf0;"></div>

==See Also==
*[[CCA-adding enzyme 3D structures|CCA-adding enzyme 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Augustin MA]]
[[Category: Betat H]]
[[Category: Huber R]]
[[Category: Moerl M]]
[[Category: Reichert AS]]
[[Category: Steegborn C]]