Cover image

Bacterial Cas12i-crRNA binary complex (PDB id: 7D8C; Zhang B, Luo D, Li Y, Perculija V, Chen J, Lin J, Ye Y, Ouyang S. 2021. Mechanistic insights into the R-loop formation and cleavage in CRISPR-Cas12i1. Nat Commun 12: 3476). Cas12i is a newly identified member of the functionally diverse type V CRISPR-Cas effectors, shown here in a complex with a 38 residue CRISPR RNA (crRNA) target interrogation mimic. Formation of a 19-bp crRNA–DNA heteroduplex (see related PDB id 7EU9) triggers a conformational rearrangement that unleashes DNase activity. RNA backbone is displayed as a red ribbon; block bases use NDB colors: A—red, C—yellow, G—green, U—cyan; protein is displayed as a gold ribbon. Cover image provided by the Nucleic Acid Database (ndbserver.rutgers.edu). Image generated using DSSR and PyMOL (Lu XJ. 2020. Nucleic Acids Res 48: e74)