View source for 6opm


==Casposase bound to integration product==
<StructureSection load='6opm' size='340' side='right'caption='[[6opm]], [[Resolution|resolution]] 3.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6opm]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Methanosarcina_mazei Methanosarcina mazei]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6OPM OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6OPM 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]] 3.1&#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>, <scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</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=6opm FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6opm OCA], [https://pdbe.org/6opm PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6opm RCSB], [https://www.ebi.ac.uk/pdbsum/6opm PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6opm ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/A0A0F8IEL4_METMZ A0A0F8IEL4_METMZ] CRISPR (clustered regularly interspaced short palindromic repeat), is an adaptive immune system that provides protection against mobile genetic elements (viruses, transposable elements and conjugative plasmids). CRISPR clusters contain spacers, sequences complementary to antecedent mobile elements, and target invading nucleic acids. CRISPR clusters are transcribed and processed into CRISPR RNA (crRNA). Acts as a dsDNA endonuclease. Involved in the integration of spacer DNA into the CRISPR cassette.[HAMAP-Rule:MF_01470]
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== Publication Abstract from PubMed ==
Key to CRISPR-Cas adaptive immunity is maintaining an ongoing record of invading nucleic acids, a process carried out by the Cas1-Cas2 complex that integrates short segments of foreign genetic material (spacers) into the CRISPR locus. It is hypothesized that Cas1 evolved from casposases, a novel class of transposases. We show here that the Methanosarcina mazei casposase can integrate varied forms of the casposon end in vitro, and recapitulates several properties of CRISPR-Cas integrases including site-specificity. The X-ray structure of the casposase bound to DNA representing the product of integration reveals a tetramer with target DNA bound snugly between two dimers in which single-stranded casposon end binding resembles that of spacer 3'-overhangs. The differences between transposase and CRISPR-Cas integrase are largely architectural, and it appears that evolutionary change involved changes in protein-protein interactions to favor Cas2 binding over tetramerization; this in turn led to preferred integration of single spacers over two transposon ends.

Casposase structure and the mechanistic link between DNA transposition and spacer acquisition by CRISPR-Cas.,Hickman AB, Kailasan S, Genzor P, Haase AD, Dyda F Elife. 2020 Jan 8;9. pii: 50004. doi: 10.7554/eLife.50004. PMID:31913120<ref>PMID:31913120</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 6opm" style="background-color:#fffaf0;"></div>

==See Also==
*[[Endonuclease 3D structures|Endonuclease 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Methanosarcina mazei]]
[[Category: Dyda F]]
[[Category: Hickman AB]]
[[Category: Kailasan S]]