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-Structure paper
タイトル | Structural basis for RNA-guided DNA cleavage by IscB-ωRNA and mechanistic comparison with Cas9. |
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ジャーナル・号・ページ | Science, Vol. 376, Issue 6600, Page 1476-1481, Year 2022 |
掲載日 | 2022年6月24日 |
著者 | Gabriel Schuler / Chunyi Hu / Ailong Ke / |
PubMed 要旨 | 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 ...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. |
リンク | Science / PubMed:35617371 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 2.74 - 3.2 Å |
構造データ | EMDB-26782, PDB-7utn: EMDB-26976, PDB-8csz: EMDB-26994, PDB-8ctl: |
化合物 | ChemComp-MG: ChemComp-ZN: |
由来 |
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キーワード | RNA BINDING PROTEIN/RNA/DNA / CRISPR / IscB / HEARO RNA / omega RNA / RNA BINDING PROTEIN-RNA-DNA complex |