View source for 5ueg


==RNA primer-template complex with guanosine dinucleotide G(5')pppp(5')G ligand==
<StructureSection load='5ueg' size='340' side='right'caption='[[5ueg]], [[Resolution|resolution]] 2.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5ueg]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5UEG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5UEG 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]] 2.6&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=86P:[[(2~{R},3~{S},4~{R},5~{R})-5-(2-azanyl-6-oxidanylidene-1~{H}-purin-9-yl)-3,4-bis(oxidanyl)oxolan-2-yl]methoxy-oxidanyl-phosphoryl]+[[[(2~{R},3~{S},4~{R},5~{R})-5-(2-azanyl-6-oxidanylidene-1~{H}-purin-9-yl)-3,4-bis(oxidanyl)oxolan-2-yl]methoxy-oxidanyl-phosphoryl]oxy-oxidanyl-phosphoryl]+hydrogen+phosphate'>86P</scene>, <scene name='pdbligand=LCC:[(1R,3R,4R,7S)-7-HYDROXY-3-(5-METHYLCYTOSIN-1-YL)-2,5-DIOXABICYCLO[2.2.1]HEPT-1-YL]METHYL+DIHYDROGEN+PHOSPHATE'>LCC</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=5ueg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5ueg OCA], [https://pdbe.org/5ueg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5ueg RCSB], [https://www.ebi.ac.uk/pdbsum/5ueg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5ueg ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
The nonenzymatic copying of RNA templates with imidazole-activated nucleotides is a well-studied model for the emergence of RNA self-replication during the origin of life. We have recently discovered that this reaction can proceed through the formation of an imidazolium-bridged dinucleotide intermediate that reacts rapidly with the primer. To gain insight into the relationship between the structure of this intermediate and its reactivity, we cocrystallized an RNA primer-template complex with a close analog of the intermediate, the triphosphate-bridged guanosine dinucleotide GpppG, and solved a high-resolution X-ray structure of the complex. The structure shows that GpppG binds the RNA template through two Watson-Crick base pairs, with the primer 3'-hydroxyl oriented to attack the 5'-phosphate of the adjacent G residue. Thus, the GpppG structure suggests that the bound imidazolium-bridged dinucleotide intermediate would be preorganized to react with the primer by in-line SN2 substitution. The structures of bound GppG and GppppG suggest that the length and flexibility of the 5'-5' linkage are important for optimal preorganization of the complex, whereas the position of the 5'-phosphate of bound pGpG explains the slow rate of oligonucleotide ligation reactions. Our studies provide a structural interpretation for the observed reactivity of the imidazolium-bridged dinucleotide intermediate in nonenzymatic RNA primer extension.

Insight into the mechanism of nonenzymatic RNA primer extension from the structure of an RNA-GpppG complex.,Zhang W, Tam CP, Walton T, Fahrenbach AC, Birrane G, Szostak JW Proc Natl Acad Sci U S A. 2017 Jul 18;114(29):7659-7664. doi:, 10.1073/pnas.1704006114. Epub 2017 Jul 3. PMID:28673998<ref>PMID:28673998</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5ueg" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Szostak JW]]
[[Category: Tam CP]]
[[Category: Zhang W]]