+ Open data
Open data
- Basic information
Basic information
| Entry |  | |||||||||
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| Title | Cryo-EM structure of the Cas9d-sgRNA-target DNA complex | |||||||||
|  Map data | ||||||||||
|  Sample | 
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|  Keywords | a protein complex / ANTIVIRAL PROTEIN | |||||||||
| Biological species | metagenome (others) | |||||||||
| Method | single particle reconstruction / cryo EM / Resolution: 2.65 Å | |||||||||
|  Authors | Zhang H / Li X / Liu Z | |||||||||
| Funding support |  China, 1 items 
 | |||||||||
|  Citation |  Journal: Nat Commun / Year: 2025 Title: Insights into the compact CRISPR-Cas9d system. Authors: Jie Yang / Tongyao Wang / Ying Huang / Zhaoyi Long / Xuzichao Li / Shuqin Zhang / Lingling Zhang / Zhikun Liu / Qian Zhang / Huabing Sun / Minjie Zhang / Hang Yin / Zhongmin Liu / Heng Zhang /  Abstract: Cas9d, the smallest known member of the Cas9 family, employs a compact domain architecture for effective target cleavage. However, the underlying mechanism remains unclear. Here, we present the cryo- ...Cas9d, the smallest known member of the Cas9 family, employs a compact domain architecture for effective target cleavage. However, the underlying mechanism remains unclear. Here, we present the cryo-EM structures of the Cas9d-sgRNA complex in both target-free and target-bound states. Biochemical assays elucidated the PAM recognition and DNA cleavage mechanisms of Cas9d. Structural comparisons revealed that at least 17 base pairs in the guide-target heteroduplex is required for nuclease activity. Beyond its typical role as an adaptor between Cas9 enzymes and targets, the sgRNA also provides structural support and functional regulation for Cas9d. A segment of the sgRNA scaffold interacts with the REC domain to form a functional target recognition module. Upon target binding, this module undergoes a coordinated conformational rearrangement, enabling heteroduplex propagation and facilitating nuclease activity. This hybrid functional module precisely monitors heteroduplex complementarity, resulting in a lower mismatch tolerance compared to SpyCas9. Moreover, structure-guided engineering in both the sgRNA and Cas9d protein led to a more compact Cas9 system with well-maintained nuclease activity. Altogether, our findings provide insights into the target recognition and cleavage mechanisms of Cas9d and shed light on the development of high-fidelity mini-CRISPR tools. | |||||||||
| History | 
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- Structure visualization
Structure visualization
| Supplemental images | 
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- Downloads & links
Downloads & links
-EMDB archive
| Map data |  emd_60006.map.gz | 97.1 MB |  EMDB map data format | |
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| Header (meta data) |  emd-60006-v30.xml  emd-60006.xml | 20.9 KB 20.9 KB | Display Display |  EMDB header | 
| FSC (resolution estimation) |  emd_60006_fsc.xml | 9.8 KB | Display |  FSC data file | 
| Images |  emd_60006.png | 92.8 KB | ||
| Filedesc metadata |  emd-60006.cif.gz | 6.7 KB | ||
| Others |  emd_60006_half_map_1.map.gz  emd_60006_half_map_2.map.gz | 95.7 MB 95.7 MB | ||
| Archive directory |  http://ftp.pdbj.org/pub/emdb/structures/EMD-60006  ftp://ftp.pdbj.org/pub/emdb/structures/EMD-60006 | HTTPS FTP | 
-Validation report
| Summary document |  emd_60006_validation.pdf.gz | 852.8 KB | Display |  EMDB validaton report | 
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| Full document |  emd_60006_full_validation.pdf.gz | 852.4 KB | Display | |
| Data in XML |  emd_60006_validation.xml.gz | 17.9 KB | Display | |
| Data in CIF |  emd_60006_validation.cif.gz | 22.9 KB | Display | |
| Arichive directory |  https://ftp.pdbj.org/pub/emdb/validation_reports/EMD-60006  ftp://ftp.pdbj.org/pub/emdb/validation_reports/EMD-60006 | HTTPS FTP | 
-Related structure data
- Links
Links
| EMDB pages |  EMDB (EBI/PDBe) /  EMDataResource | 
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- Map
Map
| File |  Download / File: emd_60006.map.gz / Format: CCP4 / Size: 103 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||
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| Projections & slices | Image control
 
 Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
| Voxel size | X=Y=Z: 0.83 Å | ||||||||||||||||||||||||||||||||||||
| Density | 
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| Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
| Details | EMDB XML: 
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-Supplemental data
-Half map: #2
| File | emd_60006_half_map_1.map | ||||||||||||
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| Projections & Slices | 
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| Density Histograms | 
-Half map: #1
| File | emd_60006_half_map_2.map | ||||||||||||
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| Projections & Slices | 
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| Density Histograms | 
- Sample components
Sample components
-Entire : a protein
| Entire | Name: a protein | 
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| Components | 
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-Supramolecule #1: a protein
| Supramolecule | Name: a protein / type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1-#4 | 
|---|---|
| Source (natural) | Organism: metagenome (others) | 
-Macromolecule #1: RNA (144-MER)
| Macromolecule | Name: RNA (144-MER) / type: rna / ID: 1 / Number of copies: 1 | 
|---|---|
| Source (natural) | Organism: metagenome (others) | 
| Molecular weight | Theoretical: 51.127133 KDa | 
| Sequence | String: GGUUCGAAAU UAGGUGCGCU UCGCGUUACA GUUAAGGCUC UGAAAAGAGC CUUAAUUGUA AAACGCCUAU ACAGUGAAGG  GAUAUACGC UUGGGUUUGU CCAGCCUGAG CCUCUAUGCC AGAAAUGGCG CCUUCAUCGU GGGUUAGGAC AUUUAAUUUU | 
-Macromolecule #2: DNA (32-MER)
| Macromolecule | Name: DNA (32-MER) / type: dna / ID: 2 / Number of copies: 1 / Classification: DNA | 
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| Source (natural) | Organism: metagenome (others) | 
| Molecular weight | Theoretical: 11.27125 KDa | 
| Sequence | String: (DC)(DA)(DT)(DT)(DT)(DG)(DA)(DC)(DC)(DC) (DG)(DC)(DG)(DA)(DA)(DG)(DC)(DG)(DC)(DA)  (DC)(DC)(DT)(DA)(DA)(DT)(DT)(DT)(DC) (DG)(DA)(DA)(DG)(DC)(DC)(DC)(DT) | 
-Macromolecule #4: DNA (5'-D(P*CP*GP*GP*GP*TP*CP*AP*AP*AP*TP*G)-3')
| Macromolecule | Name: DNA (5'-D(P*CP*GP*GP*GP*TP*CP*AP*AP*AP*TP*G)-3') / type: dna / ID: 4 / Number of copies: 1 / Classification: DNA | 
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| Source (natural) | Organism: metagenome (others) | 
| Molecular weight | Theoretical: 11.502379 KDa | 
| Sequence | String: (DA)(DG)(DG)(DG)(DC)(DT)(DT)(DC)(DG)(DA) (DA)(DA)(DT)(DT)(DA)(DG)(DG)(DT)(DG)(DC)  (DG)(DC)(DT)(DT)(DC)(DG)(DC)(DG)(DG) (DG)(DT)(DC)(DA)(DA)(DA)(DT)(DG) | 
-Macromolecule #3: a protein
| Macromolecule | Name: a protein / type: protein_or_peptide / ID: 3 / Number of copies: 1 / Enantiomer: LEVO | 
|---|---|
| Source (natural) | Organism: metagenome (others) | 
| Molecular weight | Theoretical: 86.585766 KDa | 
| Recombinant expression | Organism:   Escherichia coli (E. coli) | 
| Sequence | String: MERELVLGIA YGGKYTGLAV VDRRHNQVLY ANRLKMRDDV AGILKDRRKQ RGIRRTAQTK KKRLRELKNY LKSIGYNEST  ATFETVYSL AHKRGYDYAD MPEEKTSEEI EAMDVEERKQ WEKEKQEWEE TKRNSRHRKE VVKDVHKAMI EGRATEEQIK R VERIFNKQ  ...String: MERELVLGIA YGGKYTGLAV VDRRHNQVLY ANRLKMRDDV AGILKDRRKQ RGIRRTAQTK KKRLRELKNY LKSIGYNEST  ATFETVYSL AHKRGYDYAD MPEEKTSEEI EAMDVEERKQ WEKEKQEWEE TKRNSRHRKE VVKDVHKAMI EGRATEEQIK R VERIFNKQ YRPKRFNNRI LTKCKVEDCG VNTPLRKNVR DLLIENIVRF FPIEQSEKDN LKDAVLDKNR REEVKSFFRK HK TDEHIRK QVYDIADNKL SGRTVFCKEH ILEHTEHSKE ERKVFRLAPS LKTKIENVLA VIKDEILPKF TVNKVVMESN NFD IAAKTQ GKKRLAKEEY GKGPREGKET RKEALLRETD GRCIYCGKSI DISNAHDDAI FPRKAGGLNI FANLVACCAV CNEN KKGRT PLESGISPKP EIIAFMKNDL KKKILEDARN INTVDFNKYM SHASIGWRYM RDRLRESAGN KKLPIERQSG IYTAY FRRW WGFKKERGNT LHHALDAVIL ASRKGYSDDG LVDMTLKPKY NKGGEFDPEK HLPEPIEFKM DKGSRGSALH DRNPLS YKK GIITRRFMVT EIECGKEDDV ISETYREKLK EAFKRFDTKK GKCLTDKEAK EAGFCIKKNE LVMSLKCSIK GTGPGQM IR INNNVFKTNV HNVGVDVYLD EKGKKKAYER KNPRLSKHFI EPPPQPNGRV SFTLKRRDMV TVEGEDAIYR IKKLGTSP T IEAVVGSDGK TRTVSATKLT KANSAE | 
-Macromolecule #5: ZINC ION
| Macromolecule | Name: ZINC ION / type: ligand / ID: 5 / Number of copies: 1 / Formula: ZN | 
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| Molecular weight | Theoretical: 65.409 Da | 
-Experimental details
-Structure determination
| Method | cryo EM | 
|---|---|
|  Processing | single particle reconstruction | 
| Aggregation state | particle | 
- Sample preparation
Sample preparation
| Buffer | pH: 7.5 | 
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| Vitrification | Cryogen name: ETHANE | 
- Electron microscopy
Electron microscopy
| Microscope | TFS KRIOS | 
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| Image recording | Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) / Average electron dose: 50.0 e/Å2 | 
| Electron beam | Acceleration voltage: 300 kV / Electron source:  FIELD EMISSION GUN | 
| Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal defocus max: 1.6 µm / Nominal defocus min: 0.8 µm | 
| Experimental equipment |  Model: Titan Krios / Image courtesy: FEI Company | 
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