View source for 7el1


==Structure of a protein from bacteria==
<StructureSection load='7el1' size='340' side='right'caption='[[7el1]], [[Resolution|resolution]] 2.22&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7el1]] is a 5 chain structure with sequence from [https://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7EL1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7EL1 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]] 2.22&#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=7el1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7el1 OCA], [https://pdbe.org/7el1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7el1 RCSB], [https://www.ebi.ac.uk/pdbsum/7el1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7el1 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CAS9_STAAU CAS9_STAAU] 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). In type II CRISPR systems correct processing of pre-crRNA requires a trans-encoded small RNA (tracrRNA), endogenous ribonuclease 3 (rnc) and this protein. The tracrRNA serves as a guide for ribonuclease 3-aided processing of pre-crRNA. Subsequently Cas9/crRNA/tracrRNA endonucleolytically cleaves linear or circular dsDNA target complementary to the spacer; Cas9 is inactive in the absence of the 2 guide RNAs (gRNA). Cas9 recognizes the protospacer adjacent motif (PAM) in the CRISPR repeat sequences to help distinguish self versus nonself, as targets within the bacterial CRISPR locus do not have PAMs. PAM recognition is also required for catalytic activity.[HAMAP-Rule:MF_01480]<ref>PMID:25830891</ref> <ref>PMID:26098369</ref> 
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== Publication Abstract from PubMed ==
Bacteriophages have evolved a range of anti-CRISPR proteins (Acrs) to escape the adaptive immune system of prokaryotes, therefore Acrs can be used as switches to regulate gene editing. Herein, we report the crystal structure of a quaternary complex of AcrIIA14 bound SauCas9-sgRNA-dsDNA at 2.22 A resolution, revealing the molecular basis for AcrIIA14 recognition and inhibition. Our structural and biochemical data analysis suggest that AcrIIA14 binds to a non-conserved region of SauCas9 HNH domain that is distinctly different from AcrIIC1 and AcrIIC3, with no significant effect on sgRNA or dsDNA binding. Further, our structural data shows that the allostery of the HNH domain close to the substrate DNA is sterically prevented by AcrIIA14 binding. In addition, the binding of AcrIIA14 triggers the conformational allostery of the HNH domain and the L1 linker within the SauCas9, driving them to make new interactions with the target-guide heteroduplex, enhancing the inhibitory ability of AcrIIA14. Our research both expands the current understanding of anti-CRISPRs and provides additional culues for the rational use of the CRISPR-Cas system in genome editing and gene regulation.

Structural basis of Staphylococcus aureus Cas9 inhibition by AcrIIA14.,Liu H, Zhu Y, Lu Z, Huang Z Nucleic Acids Res. 2021 Jun 21;49(11):6587-6595. doi: 10.1093/nar/gkab487. PMID:34107040<ref>PMID:34107040</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Staphylococcus aureus]]
[[Category: Huang Z]]
[[Category: Liu H]]
[[Category: Zhu Y]]