Structure of the Cas9 protein used in CRISPR gene editing
Channel: UC Berkeley
Date: 2015-11-12

The Cas9 enzyme must flex and bend in order to bind to the guide RNA (orange). Once the Cas9-RNA complex finds its target DNA (red), the cutting region of Cas9 (yellow) will swing into place relative to its mate (blue) only when the RNA and DNA correctly match. Only then does the enzyme cut the double-stranded DNA. 

Samuel Sternberg video

http://www.berkeley.edu
http://www.facebook.com/UCBerkeley
http://twitter.com/UCBerkeley
http://instagram.com/ucberkeleyofficial
https://plus.google.com/+berkeley