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==Radiation damage study on a 16mer DNA segment, structure at 12.0 MGy dose==
<StructureSection load='6qt3' size='340' side='right'caption='[[6qt3]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6qt3]] is a 1 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=6QT3 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6QT3 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]] 1.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</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=6qt3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6qt3 OCA], [https://pdbe.org/6qt3 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6qt3 RCSB], [https://www.ebi.ac.uk/pdbsum/6qt3 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6qt3 ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
In macromolecular crystallography, a great deal of effort has been invested in understanding radiation-damage progression. While the sensitivity of protein crystals has been well characterized, crystals of DNA and of DNA-protein complexes have not thus far been studied as thoroughly. Here, a systematic investigation of radiation damage to a crystal of a DNA 16-mer diffracting to 1.8 A resolution and held at 100 K, up to an absorbed dose of 45 MGy, is reported. The RIDL (Radiation-Induced Density Loss) automated computational tool was used for electron-density analysis. Both the global and specific damage to the DNA crystal as a function of dose were monitored, following careful calibration of the X-ray flux and beam profile. The DNA crystal was found to be fairly radiation insensitive to both global and specific damage, with half of the initial diffraction intensity being lost at an absorbed average diffraction-weighted dose, D1/2, of 19 MGy, compared with 9 MGy for chicken egg-white lysozyme crystals under the same beam conditions but at the higher resolution of 1.4 A. The coefficient of sensitivity of the DNA crystal was 0.014 A(2) MGy(-1), which is similar to that observed for proteins. These results imply that the significantly greater radiation hardness of DNA and RNA compared with protein observed in a DNA-protein complex and an RNA-protein complex could be due to scavenging action by the protein, thereby protecting the DNA and RNA in these studies. In terms of specific damage, the regions of DNA that were found to be sensitive were those associated with some of the bound calcium ions sequestered from the crystallization buffer. In contrast, moieties farther from these sites showed only small changes even at higher doses.

Radiation-damage investigation of a DNA 16-mer.,Bugris V, Harmat V, Ferenc G, Brockhauser S, Carmichael I, Garman EF J Synchrotron Radiat. 2019 Jul 1;26(Pt 4):998-1009. doi:, 10.1107/S160057751900763X. Epub 2019 Jun 21. PMID:31274421<ref>PMID:31274421</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6qt3" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Brockhauser S]]
[[Category: Bugris V]]
[[Category: Carmichael I]]
[[Category: Ferenc G]]
[[Category: Garman EF]]
[[Category: Harmat V]]