Database of articles cited by EMDB/PDB/SASBDB data

Keywords
Structure methods	All X-ray diffraction NMR electron microscopy small angle scattering neutron diffraction fiber diffraction powder diffraction infrared spectroscopy EPR fluorescence transfer theoretical model Hybrid
Author
Journal
IF	>30 >20 >10 >5 all

Title	Conformational dynamics of CRISPR-Cas type I-F-HNH inform nickase engineering in a cascade scaffold.
Journal, issue, pages	Nucleic Acids Res, Vol. 54, Issue 3, Year 2026
Publish date	Jan 22, 2026
Authors	Anders Fuglsang / Sweta Suman Rout / Eliska Bartl Koutna / Nicholas Sofos / Alejandro Redondo Gallego / Guillermo Montoya /
PubMed Abstract	The type I-FHNH CRISPR-Cas system is a non-canonical Class 1 effector complex distinguished by the replacement of the Cas3 recruitment domain with a catalytic HNH domain in Cas8, enabling autonomous ...The type I-FHNH CRISPR-Cas system is a non-canonical Class 1 effector complex distinguished by the replacement of the Cas3 recruitment domain with a catalytic HNH domain in Cas8, enabling autonomous DNA cleavage without accessory nucleases. Using cryo-EM, we determined high-resolution structures of the effector complex in three catalytic states-precatalytic, NTS-cleaved, and post-catalytic-revealing a dynamic trajectory of the HNH domain through inward, middle, and outward conformations. Biochemical assays demonstrated that the complex cleaves the nontarget strand (NTS) prior to the target strand (TS), consistent with a sequential cleavage mechanism similar to Cas12 effectors but notably lacking trans-cleavage activity on single-stranded DNA. Structural comparisons confirmed a minimal PAM requirement (5'-CN) and a constrained HNH catalytic site poised for precise strand scission. We engineered a ΔLinker variant of Cas8 that repositions the HNH domain, selectively abolishing TS cleavage and converting the system into a programmable NTS-specific nickase. Importantly, we validated the functionality of both wild-type and mutant complexes in human cells. While the wild-type system induced indels and base substitutions, the ΔLinker variant triggered targeted single-strand nicks without double-stranded breaks. Together, our work establishes type I-FHNH as a compact and precise genome editing platform with in vivo efficacy.
External links	Nucleic Acids Res / PubMed:41603736 / PubMed Central
Methods	EM (single particle)
Resolution	1.75 - 3.93 Å
Structure data	54919 9shx EMDB-54919, PDB-9shx: Type I-F_HNH variant Cascade bound to dsDNA, HNH domain in middle position Method: EM (single particle) / Resolution: 2.4 Å 54931 9sit EMDB-54931, PDB-9sit: Type I-F_HNH variant Cascade bound to dsDNA, HNH domain in inwards position Method: EM (single particle) / Resolution: 1.75 Å 54932 9siu EMDB-54932, PDB-9siu: Type I-F_HNH variant Cascade bound to dsDNA, HNH domain in outwards position Method: EM (single particle) / Resolution: 2.64 Å 54943 9sjc EMDB-54943, PDB-9sjc: Type I-F_HNH variant Cascade bound to dsDNA, HNH domain in middle position Method: EM (single particle) / Resolution: 1.92 Å 54944 9sjd EMDB-54944, PDB-9sjd: Type I-F_HNH variant Cascade bound to dsDNA, HNH domain in outwards position Method: EM (single particle) / Resolution: 3.05 Å 54946 9sjl EMDB-54946, PDB-9sjl: Type I-F_HNH variant Cascade bound to dsDNA, HNH domain in inwards position Method: EM (single particle) / Resolution: 3.93 Å 54947 9sjm EMDB-54947, PDB-9sjm: Type I-F_HNH variant Cascade target-free RNP, HNH domain in inwards position Method: EM (single particle) / Resolution: 3.13 Å 54948 9sjn EMDB-54948, PDB-9sjn: Type I-F_HNH variant Cascade target-free RNP, HNH domain in outwards position Method: EM (single particle) / Resolution: 3.03 Å EMDB-54949: Type I-F_HNH variant Cascade RNP bound to dsDNA with trace of target strand into HNH domain rotated in middle position Method: EM (single particle) / Resolution: 3.06 Å 54950 9sjo EMDB-54950, PDB-9sjo: Type I-F_HNH variant Cascade target-free RNP, HNH domain in middle position Method: EM (single particle) / Resolution: 3.07 Å
Chemicals	ChemComp-MG: Unknown entry ChemComp-HOH: WATER
Source	selenomonas sp. (bacteria)
Keywords	RNA BINDING PROTEIN / CRISPR-Cas Type I-F HNH nuclease