Sandbox Reserved 1750: Difference between revisions

Line 12:

The SaCas9 recognizes the sgRNA scaffold within the <scene name='92/925538/Lobes_and_linkers/20'>REC lobe and WED domain</scene>. The WED contains five stranded beta sheets flanked with four alpha helices to allow binding of the repeat: anti-repeat duplex. REC lob binds the scaffold and secures it into the SaCas9 <ref name="Cas9" />.

== Endonuclease Activity of Cas9 ==

Finally, <scene name='92/925538/Lobes_and_linkers/12'>RuvC and HNH</scene> are involved in endonuclease activity. RuvC uses two manganese ions to cleave the non-target DNA through manganese coordinating with the phosphate backbone and aspartic acid residues. These phosphate oxygens coordinated with the manganese makes the phosphate a greater target for nucleophillic attack.A histidine then acts as a base to create a hydroxide nucleophile that attacks the phosphate bond and cleaves the non-target DNA. The binding of the RuvC to the target DNA changes the conformation of a linker protein region between the RuvC domain and the HNH domain. The conformational change of the linker brings the HNH domain close enough to the target DNA to cut the DNA. The HNH follows a similar mechanism as to RuvC using a histidine base to create a hydroxide ion nucleophile that attacks the phosphate bond using one manganese ion instead of two. This is modeled as manganese however, it magnesium is used in cells <ref name="Cas9" />.

Finally, <scene name='92/925538/Lobes_and_linkers/12'>RuvC and HNH</scene> are involved in endonuclease activity. RuvC uses two manganese ions to cleave the non-target DNA through manganese coordinating with the phosphate backbone and aspartic acid residues. These phosphate oxygens coordinated with the manganese makes the phosphate a greater target for nucleophillic attack.A histidine then acts as a base to create a hydroxide nucleophile that attacks the phosphate bond and cleaves the non-target DNA. The binding of the RuvC to the target DNA changes the conformation of a linker protein region between the RuvC domain and the HNH domain. The conformational change of the linker brings the HNH domain close enough to the target DNA to cut the DNA. This linker confromational change is not present in the crystal structure, therefore the HNH appears to be far from the target DNA. The HNH follows a similar mechanism as to RuvC using a histidine base to create a hydroxide ion nucleophile that attacks the phosphate bond using one manganese ion instead of two. This is modeled as manganese however, it magnesium is used in cells <ref name="Cas9" />.

</structuresection>

==References==

Sandbox Reserved 1750: Difference between revisions

Navigation menu

Page actions

Page actions

Personal tools

Navigation

Search

Tools

@@ Line 12: / Line 12: @@
 The SaCas9 recognizes the sgRNA scaffold within the <scene name='92/925538/Lobes_and_linkers/20'>REC lobe and WED domain</scene>. The WED contains five stranded beta sheets flanked with four alpha helices to allow binding of the repeat: anti-repeat duplex. REC lob binds the scaffold and secures it into the SaCas9 <ref name="Cas9" />.
 == Endonuclease Activity of Cas9 ==
-Finally, <scene name='92/925538/Lobes_and_linkers/12'>RuvC and HNH</scene> are involved in endonuclease activity. RuvC uses two manganese ions to cleave the non-target DNA through manganese coordinating with the phosphate backbone and aspartic acid residues. These phosphate oxygens coordinated with the manganese makes the phosphate a greater target for nucleophillic attack.A histidine then acts as a base to create a hydroxide nucleophile that attacks the phosphate bond and cleaves the non-target DNA. The binding of the RuvC to the target DNA changes the conformation of a linker protein region between the RuvC domain and the HNH domain. The conformational change of the linker brings the HNH domain close enough to the target DNA to cut the DNA. The HNH follows a similar mechanism as to RuvC using a histidine base to create a hydroxide ion nucleophile that attacks the phosphate bond using one manganese ion instead of two. This is modeled as manganese however, it magnesium is used in cells <ref name="Cas9" />.
+Finally, <scene name='92/925538/Lobes_and_linkers/12'>RuvC and HNH</scene> are involved in endonuclease activity. RuvC uses two manganese ions to cleave the non-target DNA through manganese coordinating with the phosphate backbone and aspartic acid residues. These phosphate oxygens coordinated with the manganese makes the phosphate a greater target for nucleophillic attack.A histidine then acts as a base to create a hydroxide nucleophile that attacks the phosphate bond and cleaves the non-target DNA. The binding of the RuvC to the target DNA changes the conformation of a linker protein region between the RuvC domain and the HNH domain. The conformational change of the linker brings the HNH domain close enough to the target DNA to cut the DNA. This linker confromational change is not present in the crystal structure, therefore the HNH appears to be far from the target DNA. The HNH follows a similar mechanism as to RuvC using a histidine base to create a hydroxide ion nucleophile that attacks the phosphate bond using one manganese ion instead of two. This is modeled as manganese however, it magnesium is used in cells <ref name="Cas9" />.
 </structuresection>
 ==References==
 <references />