Download MendeleyAllosteric control of type I-A CRISPR-Cas3 complexes and establishment as effective nucleic acid detection and human genome editing tools.
Hu, C., Ni, D., Nam, K.H., Majumdar, S., McLean, J., Stahlberg, H., Terns, M.P., Ke, A.(2022) Mol Cell 82: 2754-2768.e5
- PubMed: 35835111
- DOI: https://doi.org/10.1016/j.molcel.2022.06.007
- Primary Citation of Related Structures:
7TR6, 7TR8, 7TR9, 7TRA - PubMed Abstract:
Type I CRISPR-Cas systems typically rely on a two-step process to degrade DNA. First, an RNA-guided complex named Cascade identifies the complementary DNA target. The helicase-nuclease fusion enzyme Cas3 is then recruited in trans for processive DNA degradation. Contrary to this model, here, we show that type I-A Cascade and Cas3 function as an integral effector complex. We provide four cryoelectron microscopy (cryo-EM) snapshots of the Pyrococcus furiosus (Pfu) type I-A effector complex in different stages of DNA recognition and degradation. The HD nuclease of Cas3 is autoinhibited inside the effector complex. It is only allosterically activated upon full R-loop formation, when the entire targeted region has been validated by the RNA guide. The mechanistic insights inspired us to convert Pfu Cascade-Cas3 into a high-sensitivity, low-background, and temperature-activated nucleic acid detection tool. Moreover, Pfu CRISPR-Cas3 shows robust bi-directional deletion-editing activity in human cells, which could find usage in allele-specific inactivation of disease-causing mutations.
Organizational Affiliation:
Department of Molecular Biology and Genetics, Cornell University, 253 Biotechnology Building, Ithaca, NY 14853, USA.
