View source for 5ds4


==Crystal structure the Escherichia coli Cas1-Cas2 complex bound to protospacer DNA==
<StructureSection load='5ds4' size='340' side='right'caption='[[5ds4]], [[Resolution|resolution]] 3.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5ds4]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12] and [https://en.wikipedia.org/wiki/Escherichia_virus_M13 Escherichia virus M13]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5DS4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5DS4 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]] 3.2&#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=5ds4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5ds4 OCA], [https://pdbe.org/5ds4 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5ds4 RCSB], [https://www.ebi.ac.uk/pdbsum/5ds4 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5ds4 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CAS2_ECOLI CAS2_ECOLI] 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 sequences complementary to antecedent mobile elements and target invading nucleic acids. CRISPR clusters are transcribed and processed into CRISPR RNA (crRNA). Functions as a ssRNA-specific endoribonuclease (By similarity).<ref>PMID:21255106</ref> 
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== Publication Abstract from PubMed ==
Bacteria and archaea generate adaptive immunity against phages and plasmids by integrating foreign DNA of specific 30-40-base-pair lengths into clustered regularly interspaced short palindromic repeat (CRISPR) loci as spacer segments. The universally conserved Cas1-Cas2 integrase complex catalyses spacer acquisition using a direct nucleophilic integration mechanism similar to retroviral integrases and transposases. How the Cas1-Cas2 complex selects foreign DNA substrates for integration remains unknown. Here we present X-ray crystal structures of the Escherichia coli Cas1-Cas2 complex bound to cognate 33-nucleotide protospacer DNA substrates. The protein complex creates a curved binding surface spanning the length of the DNA and splays the ends of the protospacer to allow each terminal nucleophilic 3'-OH to enter a channel leading into the Cas1 active sites. Phosphodiester backbone interactions between the protospacer and the proteins explain the sequence-nonspecific substrate selection observed in vivo. Our results uncover the structural basis for foreign DNA capture and the mechanism by which Cas1-Cas2 functions as a molecular ruler to dictate the sequence architecture of CRISPR loci.

Foreign DNA capture during CRISPR-Cas adaptive immunity.,Nunez JK, Harrington LB, Kranzusch PJ, Engelman AN, Doudna JA Nature. 2015 Nov 26;527(7579):535-8. doi: 10.1038/nature15760. Epub 2015 Oct 21. PMID:26503043<ref>PMID:26503043</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Endonuclease 3D structures|Endonuclease 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli K-12]]
[[Category: Escherichia virus M13]]
[[Category: Large Structures]]
[[Category: Doudna JA]]
[[Category: Engelman AN]]
[[Category: Harrington LB]]
[[Category: Kranzusch PJ]]
[[Category: Nunez JK]]