Structure-based evolutionary relationship between IscB and Cas9

In a recent study published in Science, Ailong Ke and coworkers determined the cryo-EM structure of the dsDNA-bound IscB(omega RNA) ribonucleoprotein (RNP) complex, which was supplemented with complementary biochemical experiments, revealing the architectural and mechanistic similarities for RNA-guided DNA recognition and activation-mediated cleavage by IscB and Cas9 RNPs. These findings highlight the evolutionary relationship between IscB and Cas9, and the potential for development of enhanced and programmable genome editing tools by capitalizing on IscB's small size.