CRISPR Cas9 Bound to Guide RNA and Target DNA
Clustered regularly interspaced short palindromic repeats (CRISPR, pronounced crisper) are segments of prokaryotic DNA containing short, repetitive base sequences. In a palindromic repeat, the sequence of nucleotides is the same in both directions. Each repetition is followed by short segments of spacer DNA from previous exposures to foreign DNA (e.g., a virus or plasmid). Small clusters of cas (CRISPR-associated system) genes are located next to CRISPR sequences.
3D Molecular Visualization
Cpf1 is an RNA-guided endonuclease of a type V CRISPR-Cas system that has been recently harnessed for genome editing. Here, we report the crystal structure of Acidaminococcus sp. Cpf1 (AsCpf1) in complex with the guide RNA and its target DNA at 2.8 Å resolution. AsCpf1 adopts a bilobed architecture, with the RNA-DNA heteroduplex bound inside the central channel. The structural comparison of AsCpf1 with Cas9, a type II CRISPR-Cas nuclease, reveals both striking similarity and major differences, thereby explaining their distinct functionalities. AsCpf1 contains the RuvC domain and a putative novel nuclease domain, which are responsible for cleaving the non-target and target strands, respectively, and for jointly generating staggered DNA double-strand breaks. AsCpf1 recognizes the 5′-TTTN-3′ protospacer adjacent motif by base and shape readout mechanisms. Our findings provide mechanistic insights into RNA-guided DNA cleavage by Cpf1 and establish a framework for rational engineering of the CRISPR-Cpf1 toolbox. “http://www.rcsb.org/pdb/explore.do?structureId=5B43
Purchase 3D Prints
This is a 3D print of CRISPR Ca9 is created in full-color sandstone. The model depicts CRISPR (purple) bound to its guide RNA (red) while editing its Target DNA (yellow and green). The subtle color variations in the CRISPR are associated with its bFactor, or atomic temperature. The darker the color, the less the protein moves with a cooler atomic temperature.