View source for 1q78

==Crystal structure of poly(A) polymerase in complex with 3'-dATP and magnesium chloride==
<StructureSection load='1q78' size='340' side='right' caption='[[1q78]], [[Resolution|resolution]] 2.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1q78]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Bovin Bovin]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Q78 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1Q78 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=3AT:3-DEOXYADENOSINE-5-TRIPHOSPHATE'>3AT</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>
<tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=CSD:3-SULFINOALANINE'>CSD</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1q79|1q79]]</td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">PAPOLA OR PAP ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9913 BOVIN])</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Polynucleotide_adenylyltransferase Polynucleotide adenylyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.19 2.7.7.19] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1q78 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1q78 OCA], [http://pdbe.org/1q78 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1q78 RCSB], [http://www.ebi.ac.uk/pdbsum/1q78 PDBsum]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/PAPOA_BOVIN PAPOA_BOVIN]] Polymerase that creates the 3'-poly(A) tail of mRNA's. Also required for the endoribonucleolytic cleavage reaction at some polyadenylation sites. May acquire specificity through interaction with a cleavage and polyadenylation specificity factor (CPSF) at its C-terminus.<ref>PMID:9463383</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/q7/1q78_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=1q78 ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Polyadenylation of messenger RNA precursors is an essential process in eukaryotes. Poly(A) polymerase (PAP), a member of the nucleotidyltransferase family that includes DNA polymerase beta, incorporates ATP at the 3' end of mRNAs in a template-independent manner. Although the structures of mammalian and yeast PAPs are known, their mechanism of ATP selection has remained elusive. In a recent bovine PAP structure complexed with an analog of ATP and Mn2+, strictly conserved residues interact selectively with the adenine base, but the nucleotide was found in a "non-productive" conformation. Here we report a second bovine crystal structure, obtained in the presence of Mg2+, where 3'-dATP adopts a "productive" conformation similar to that seen in yeast PAP or DNA polymerase beta. Mutational analysis and activity assays with ATP analogs suggest a role in catalysis for one of the two adenine-binding sites revealed by our structural data. The other site might function to prevent futile hydrolysis of ATP. In order to investigate the role of metals in catalysis we performed steady state kinetics experiments under distributive polymerization conditions. These tests suggest a sequential random mechanism in vitro in the presence of ATP and RNA, without preference for a particular order of binding of the two substrates. In vivo, however, where polyadenylation is processive and the primer does not dissociate from the enzyme, an ordered mechanism with the primer as the leading substrate is more likely.

Biochemical and structural insights into substrate binding and catalytic mechanism of mammalian poly(A) polymerase.,Martin G, Moglich A, Keller W, Doublie S J Mol Biol. 2004 Aug 20;341(4):911-25. PMID:15328606<ref>PMID:15328606</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 1q78" style="background-color:#fffaf0;"></div>

==See Also==
*[[Poly(A) Polymerase|Poly(A) Polymerase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bovin]]
[[Category: Polynucleotide adenylyltransferase]]
[[Category: Doublie, S]]
[[Category: Keller, W]]
[[Category: Martin, G]]
[[Category: Moglich, A]]
[[Category: Mrna processing]]
[[Category: Nucleotidyl transferase]]
[[Category: Transferase]]