How CRISPR proteins find their target

In addition to the Cas9 protein that bacteria use to bind and snip DNA, bacteria have other Cas proteins that know where to insert that viral DNA into the CRISPR region to remember which viruses have attacked and mount a defense. A research team has discovered how these proteins — Cas1 and Cas2 — locate and insert the viral DNA, and it relies on the flexibility of these enzymes and the shape of the DNA.