5xvn

From Proteopedia

(Difference between revisions)

Revision as of 08:14, 27 November 2019

E. far Cas1-Cas2/prespacer binary complex

Structural highlights

5xvn is a 16 chain structure with sequence from Enterococcus faecalis tx0027. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:
Related:	5xvo, 5xvp
Gene:	cas1, HMPREF9501_02814 (Enterococcus faecalis TX0027), cas2, HMPREF9501_02813 (Enterococcus faecalis TX0027)
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[E6GPD7_ENTFL] 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] [E6GPD6_ENTFL] 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. Involved in the integration of spacer DNA into the CRISPR cassette.[HAMAP-Rule:MF_01471]

Publication Abstract from PubMed

CRISPR (clustered regularly interspaced short palindromic repeats) and the nearby cas (CRISPR-associated) operon establish an RNA-based adaptive immunity system in prokaryotes1-5. Molecular memory is created when a short foreign DNA-derived prespacer is integrated into the CRISPR array as a new spacer6-9. Whereas the RNA-guided CRISPR interference mechanism varies widely among CRISPR-Cas systems, the spacer integration mechanism is essentially identical7-9. The conserved Cas1 and Cas2 proteins form an integrase complex consisting two distal Cas1 dimers bridged by a Cas2 dimer in the middle6,10. The prespacer is bound by Cas1-Cas2 as a dual forked DNA, and the terminal 3'-OH of each 3'-overhang serves as an attacking nucleophile during integration11-14. Importantly, the prespacer is preferentially integrated into the leader-proximal region of the CRISPR array1,7,10,15, guided by the leader sequence and a pair of inverted repeats (IRs) inside the CRISPR repeat7,15-20. Spacer integration in the most well-studied Escherichia coli Type I-E CRISPR system further relies on the bacterial Integration Host Factor (IHF)21,22. In Type II-A CRISPR, however, Cas1-Cas2 alone integrates spacer efficiently in vitro18; other Cas proteins (Cas9 and Csn2) play accessory roles in prespacer biogenesis17,23. Focusing on the Enterococcus faecalis Type II-A system24, here we report four structure snapshots of Cas1-Cas2 during spacer integration. EfaCas1-Cas2 selectively binds to a splayed 30-bp prespacer bearing 4-nt 3'-overhangs. Three molecular events take place upon encountering a target: Cas1-Cas2/prespacer first searches for half-sites stochastically, then preferentially interacts with the leader-side CRISPR repeat and catalyzes a nucleophilic attack that connects one strand of the leader-proximal repeat to the prespacer 3'-overhang. Recognition of the spacer half-site requires DNA bending and leads to full integration. We derive a mechanistic framework explaining the stepwise spacer integration process and the leader-proximal preference.

How type II CRISPR-Cas establish immunity through Cas1-Cas2-mediated spacer integration.,Xiao Y, Ng S, Nam KH, Ke A Nature. 2017 Sep 4. doi: 10.1038/nature24020. PMID:28869593^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Xiao Y, Ng S, Nam KH, Ke A. How type II CRISPR-Cas establish immunity through Cas1-Cas2-mediated spacer integration. Nature. 2017 Sep 4. doi: 10.1038/nature24020. PMID:28869593 doi:http://dx.doi.org/10.1038/nature24020

1 Structural highlights
2 Function
3 Publication Abstract from PubMed
4 See Also
5 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/5xvn"

@@ Line 1: / Line 1: @@
 ==E. far Cas1-Cas2/prespacer binary complex==
-<StructureSection load='5xvn' size='340' side='right' caption='[[5xvn]], [[Resolution|resolution]] 3.25&Aring;' scene=''>
+<StructureSection load='5xvn' size='340' side='right'caption='[[5xvn]], [[Resolution|resolution]] 3.25&Aring;' scene=''>
 == Structural highlights ==
-<table><tr><td colspan='2'>[[5xvn]] is a 16 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5XVN OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5XVN FirstGlance]. <br>
+<table><tr><td colspan='2'>[[5xvn]] is a 16 chain structure with sequence from [http://en.wikipedia.org/wiki/Enterococcus_faecalis_tx0027 Enterococcus faecalis tx0027]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5XVN OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5XVN FirstGlance]. <br>
 </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>
 <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[5xvo|5xvo]], [[5xvp|5xvp]]</td></tr>
+<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">cas1, HMPREF9501_02814 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=749498 Enterococcus faecalis TX0027]), cas2, HMPREF9501_02813 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=749498 Enterococcus faecalis TX0027])</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=5xvn FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5xvn OCA], [http://pdbe.org/5xvn PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5xvn RCSB], [http://www.ebi.ac.uk/pdbsum/5xvn PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5xvn ProSAT]</span></td></tr>
 </table>
@@ Line 19: / Line 20: @@
 </div>
 <div class="pdbe-citations 5xvn" style="background-color:#fffaf0;"></div>
+==See Also==
+*[[Endonuclease 3D structures|Endonuclease 3D structures]]
 == References ==
 <references/>
 __TOC__
 </StructureSection>
+[[Category: Enterococcus faecalis tx0027]]
+[[Category: Large Structures]]
 [[Category: Ke, A]]
 [[Category: Nam, K H]]

5xvn

From Proteopedia

Revision as of 08:14, 27 November 2019

E. far Cas1-Cas2/prespacer binary complex

Structural highlights

Function

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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