CRISPR-Cas9
From Proteopedia
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<StructureSection load='4qyz' size='450' side='right' scene='74/742625/Cv/4' caption=''> | <StructureSection load='4qyz' size='450' side='right' scene='74/742625/Cv/4' caption=''> | ||
==Crystal structure of a CRISPR RNA-guided surveillance complex, Cascade, bound to a ssDNA target<ref>PMID:25123481</ref>== | ==Crystal structure of a CRISPR RNA-guided surveillance complex, Cascade, bound to a ssDNA target<ref>PMID:25123481</ref>== | ||
| - | The <scene name='74/742625/Cv/ | + | The <scene name='74/742625/Cv/21'>crystal structure of ssDNA-bound Cascade has the seahorse architecture</scene>. The body is formed by a helical filament of six Cas7 subunits (Cas7.1 to 7.6) wrapped around the crRNA guide, with a head-to-tail dimer of Cse2 (Cse2.1 and Cse2.2) at the belly. Cas6e and the 3′ handle of crRNA cap the Cas7 filament at the head while Cas5 and the 5′ handle cap the tail. The N-terminal base of Cse1 is positioned at the tail of the filament; the C-terminal four-helix bundle contacts Cse2.2. The ssDNA target is juxtaposed to the guide region of the crRNA in a groove formed by the Cas7 filament, the four-helix bundle of Cse1, and the Cse2 dimer. |
| - | *<scene name='74/742625/Cv/ | + | *<scene name='74/742625/Cv/22'>90° rotation about axis Z</scene>. |
| - | *<scene name='74/742625/Cv/ | + | *<scene name='74/742625/Cv/23'>90° rotation about axis Y</scene>. |
The <scene name='74/742625/Cv/10'>two strands of the guide-target hybrid</scene> do not twist around one another in a helix, but instead adopt an underwound ribbon-like structure reminiscent of a ladder. The 5′ and 3′ ends of the curved target strand are ~102Å apart, roughly the length of straight B-form dsDNA with an identical sequence (~107 Å). The crRNA (green) and ssDNA target (orange) are displayed in a spheres representation. Underwinding is facilitated by <scene name='74/742625/Cv/12'>kinks that occur every sixth base pair in the backbone of both strands of the hybrid</scene> (ribbon representation of the crRNA and ssDNA). <scene name='74/742625/Cv/14'>At each kink, complementary nucleotides are rotated ~90°, in opposing directions, from the axis of the duplex</scene>. Disrupted RNA and DNA nucleotides are colored red and blue, respectively. | The <scene name='74/742625/Cv/10'>two strands of the guide-target hybrid</scene> do not twist around one another in a helix, but instead adopt an underwound ribbon-like structure reminiscent of a ladder. The 5′ and 3′ ends of the curved target strand are ~102Å apart, roughly the length of straight B-form dsDNA with an identical sequence (~107 Å). The crRNA (green) and ssDNA target (orange) are displayed in a spheres representation. Underwinding is facilitated by <scene name='74/742625/Cv/12'>kinks that occur every sixth base pair in the backbone of both strands of the hybrid</scene> (ribbon representation of the crRNA and ssDNA). <scene name='74/742625/Cv/14'>At each kink, complementary nucleotides are rotated ~90°, in opposing directions, from the axis of the duplex</scene>. Disrupted RNA and DNA nucleotides are colored red and blue, respectively. | ||
Revision as of 11:43, 22 September 2016
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References
- ↑ Mulepati S, Heroux A, Bailey S. Crystal structure of a CRISPR RNA-guided surveillance complex bound to a ssDNA target. Science. 2014 Aug 14. pii: 1256996. PMID:25123481 doi:http://dx.doi.org/10.1126/science.1256996
