Holding something real

There’s nothing like hands-on experience to figure out how something works. In that spirit, I worked with 3D Molecular Designs to get a deconstructable, 3D printed model of Cas9 doing its thing. The model is based on the Jinek lab’s recent structure of Cas9 bound to PAM-containing DNA, with some artistic license to build in the full non-complementary strand and the upstream and downstream duplexes. I think the model tuned out extremely well and beautifully illustrates how Cas9 tightly binds DNA by using the sgRNA protospacer. It also very concretely highlights some interesting mysteries about the structure, such as the HNH active site pointing towards the wrong DNA strand. Just the few hours I’ve been playing with this model have led to some neat insights.

Edit: correctly linked to 3D Molecular Designs instead of MSOE (sister organizations).

img_20141202_134820463_hdrCas9 bound to sgRNA and DNA target

img_20141202_134841524_hdrHnH domain removed (sgRNA in orange, DNA in blue)

img_20141204_083459439_hdrThe DNA and sgRNA can be removed from the model (PAM in green) img_20141204_083630753_hdrThe DNA strands can even be separated at the actual Cas9 cleavage site


Jacob Corn

Jacob Corn is the Professor of Genome Biology at ETH Zürich. Follow him on twitter @jcornlab.


  1. Reed Kelso

    Are the stl files for this beautiful model available? I’d love to print a version for the kids in my science class.

    1. Jacob Corn Post author

      I made model from a PDB, but then worked with 3D Molecular Designs at MSOE to make the model. They might be able to provide the STL files. Note that there’s a new structure recently out from the Doudna group that’s a bit mode updated. I’m working on a new model based on that structure.



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