Cas9 Sandbox: Difference between revisions
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== Function == | == Function == | ||
<StructureSection load='4un3' size='350' frame='true' align='right' caption='4un3 of Streptococcus pyogenes' scene='Insert optional scene name here' /> | <StructureSection load='4un3' size='350' frame='true' align='right' caption='4un3 of Streptococcus pyogenes' scene='Insert optional scene name here' /> | ||
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Cas9 is a structurally bilobed, containing specific domains for the recognition of target DNA and nucleases to cleave DNA strands. Each of these lobes contain three major units essential for a functional endonuclease, these are the essential <scene name='71/714945/Lobes_domain_of_cas9/5'>domains</scene>. | Cas9 is a structurally bilobed, containing specific domains for the recognition of target DNA and nucleases to cleave DNA strands. Each of these lobes contain three major units essential for a functional endonuclease, these are the essential <scene name='71/714945/Lobes_domain_of_cas9/5'>domains</scene>. | ||
The recognition lobe (REC) contains a long bridge helix, the REC-1 domain and the REC-2 domain. It is also the least conserved lobe through the types of Cas9. The long α-helix bridge, which is arginine-rich, is essential for recognizing single guide RNA-DNA complexes on target DNA. This structure has been shown to be conserved through Cas9 proteins. The REC-1 domain contains 25 α-helixes and two β-sheets, and is crucial to the function of Cas9 by recognizing a specific motif termed the repeat:anti-repeat region of the single guide RNA and DNA complex. The REC-2 domain contains six α-helix’s in a bundle but there is no current understanding of its function. | The recognition lobe (REC) contains a long bridge helix, the REC-1 domain and the REC-2 domain. It is also the least conserved lobe through the types of Cas9. The long <scene name='71/714945/Alpha_helix_bridge/1'>α-helix bridge</scene>, which is arginine-rich, is essential for recognizing single guide RNA-DNA complexes on target DNA. This structure has been shown to be conserved through Cas9 proteins. The REC-1 domain contains 25 α-helixes and two β-sheets, and is crucial to the function of Cas9 by recognizing a specific motif termed the repeat:anti-repeat region of the single guide RNA and DNA complex. The REC-2 domain contains six α-helix’s in a bundle but there is no current understanding of its function. | ||
The nuclease lobe (NUC) contains a RuvC domain, HNH domain and the PAM-interacting domain (PI). The RuvC domain is comprised of three RuvC motifs that are made up of two-stranded antiparallel β-sheets, and six-stranded β-sheets, which are flanked by nine α-helices. The RuvC nuclease cleaves the non-complementary, single stranded DNA. The HNH domain is composed of a two-stranded antiparallel β-sheet which is flanked by four α-helixes and cleaves the complementary strand of target DNA. The PI is made up of seven α-helixes and numerous strand-varying antiparallel β-sheets which recognize the PAM sequence on the non-complementary target DNA strand.<ref>PMID:24529477</ref> | The nuclease lobe (NUC) contains a RuvC domain, HNH domain and the PAM-interacting domain (PI). The RuvC domain is comprised of three RuvC motifs that are made up of two-stranded antiparallel β-sheets, and six-stranded β-sheets, which are flanked by nine α-helices. The RuvC nuclease cleaves the non-complementary, single stranded DNA. The HNH domain is composed of a two-stranded antiparallel β-sheet which is flanked by four α-helixes and cleaves the complementary strand of target DNA. The PI is made up of seven α-helixes and numerous strand-varying antiparallel β-sheets which recognize the PAM sequence on the non-complementary target DNA strand.<ref>PMID:24529477</ref> | ||