7UTN
IscB and wRNA bound to Target DNA
Summary for 7UTN
| Entry DOI | 10.2210/pdb7utn/pdb |
| EMDB information | 26782 |
| Descriptor | IscB, RNA (222-MER), DNA target strand, ... (4 entities in total) |
| Functional Keywords | crispr, iscb, hearo rna, omega rna, rna binding protein-rna-dna complex, rna binding protein/rna/dna |
| Biological source | synthetic construct More |
| Total number of polymer chains | 4 |
| Total formula weight | 165429.79 |
| Authors | Schuler, G.A.,Hu, C.,Ke, A. (deposition date: 2022-04-27, release date: 2022-06-15, Last modification date: 2024-02-14) |
| Primary citation | Schuler, G.,Hu, C.,Ke, A. Structural basis for RNA-guided DNA cleavage by IscB-omega RNA and mechanistic comparison with Cas9. Science, 376:1476-1481, 2022 Cited by PubMed Abstract: Class 2 CRISPR effectors Cas9 and Cas12 may have evolved from nucleases in IS200/IS605 transposons. IscB is about two-fifths the size of Cas9 but shares a similar domain organization. The associated ωRNA plays the combined role of CRISPR RNA (crRNA) and trans-activating CRISPR RNA tracrRNA) to guide double-stranded DNA (dsDNA) cleavage. Here we report a 2.78-angstrom cryo-electron microscopy structure of IscB-ωRNA bound to a dsDNA target, revealing the architectural and mechanistic similarities between IscB and Cas9 ribonucleoproteins. Target-adjacent motif recognition, R-loop formation, and DNA cleavage mechanisms are explained at high resolution. ωRNA plays the equivalent function of REC domains in Cas9 and contacts the RNA-DNA heteroduplex. The IscB-specific PLMP domain is dispensable for RNA-guided DNA cleavage. The transition from ancestral IscB to Cas9 involved dwarfing the ωRNA and introducing protein domain replacements. PubMed: 35617371DOI: 10.1126/science.abq7220 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (2.74 Å) |
Structure validation
Download full validation report
