This graphical abstract designed for the journal Cell visually summarizes the main findings of Guo, T. W. et al. Cryo-EM Structures Reveal Mechanism and Inhibition of DNA Targeting by a CRISPR-Cas Surveillance Complex. Cell 171, 414–426.e12 (2017).
Long before they became the hottest trend in DNA-editing technology, CRISPR systems originated in bacteria as a defense against foreign DNA from invading viruses, also known as bacteriophages. By using cryo-electron microscopy (cryo-EM), the research team was able to characterize the structure of a CRISPR complex (Csy) binding to foreign DNA (orange), as well as its structure when bound by bacteriophage inhibitors. If the bacteriophage successfully inhibits Csy, it can infect the bacterial cell.
Veronica Falconieri/Subramaniam Lab/CCR/NCI/NIH