View source for 7mpz


==HNH Nuclease Domain from G. stearothermophilus Cas9==
<StructureSection load='7mpz' size='340' side='right'caption='[[7mpz]], [[Resolution|resolution]] 2.04&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7mpz]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Geobacillus_stearothermophilus Geobacillus stearothermophilus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7MPZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7MPZ 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]] 2.04&#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=7mpz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7mpz OCA], [https://pdbe.org/7mpz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7mpz RCSB], [https://www.ebi.ac.uk/pdbsum/7mpz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7mpz ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/A0A250DVH8_GEOSE A0A250DVH8_GEOSE] 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]
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== Publication Abstract from PubMed ==
CRISPR-Cas9 is a widely used biochemical tool with applications in molecular biology and precision medicine. The RNA-guided Cas9 protein uses its HNH endonuclease domain to cleave the DNA strand complementary to its endogenous guide RNA. In this study, novel constructs of HNH from two divergent organisms, G. stearothermophilus (GeoHNH) and S. pyogenes (SpHNH) were engineered from their respective full-length Cas9 proteins. Despite low sequence similarity, the X-ray crystal structures of these constructs reveal that the core of HNH surrounding the active site is conserved. Structure prediction of the full-length GeoCas9 protein using Phyre2 and AlphaFold2 also showed that the crystallographic construct of GeoHNH represents the structure of the domain within the full-length GeoCas9 protein. However, significant differences are observed in the solution dynamics of structurally conserved regions of GeoHNH and SpHNH, the latter of which was shown to use such molecular motions to propagate the DNA cleavage signal. Indeed, molecular simulations show that the intradomain signaling pathways, which drive SpHNH function, are non-specific and poorly formed in GeoHNH. Taken together, these outcomes suggest mechanistic differences between mesophilic and thermophilic Cas9 species.

Structural and dynamic insights into the HNH nuclease of divergent Cas9 species.,Belato HB, D'Ordine AM, Nierzwicki L, Arantes PR, Jogl G, Palermo G, Lisi GP J Struct Biol. 2021 Dec 3;214(1):107814. doi: 10.1016/j.jsb.2021.107814. PMID:34871741<ref>PMID:34871741</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 7mpz" style="background-color:#fffaf0;"></div>

==See Also==
*[[Bromodomain-containing protein 3D structures|Bromodomain-containing protein 3D structures]]
*[[Endonuclease 3D structures|Endonuclease 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Geobacillus stearothermophilus]]
[[Category: Large Structures]]
[[Category: Belato HB]]
[[Category: D'Ordine AM]]
[[Category: Jogl G]]
[[Category: Lisi GP]]