Source 1primary paper2026MED
Toolkit/FnoCas12aKD2P
FnoCas12aKD2P
Also known as: FnoCas12a<KD2P>, Francisella novicida Cas12a variant with K969P/D970P substitutions
Taxonomy: Mechanism Branch / Architecture. Workflows sit above the mechanism and technique branches rather than replacing them.
Summary
we previously developed a Francisella novicida Cas12a variant (FnoCas12a) by introducing double proline substitutions (K969P/D970P) in a conserved arginine-rich helix called the bridge helix (BH)
Usefulness & Problems
Why this is useful
FnoCas12aKD2P is a double-proline bridge-helix variant of Francisella novicida Cas12a used here to probe conformational activation states. The paper links this variant to altered bridge-helix behavior relevant to R-loop formation and RuvC activation.; probing bridge-helix-mediated activation of Cas12a; mitigating off-target DNA cleavage of Cas12a
Source:
FnoCas12aKD2P is a double-proline bridge-helix variant of Francisella novicida Cas12a used here to probe conformational activation states. The paper links this variant to altered bridge-helix behavior relevant to R-loop formation and RuvC activation.
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probing bridge-helix-mediated activation of Cas12a
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mitigating off-target DNA cleavage of Cas12a
Problem solved
The variant was previously developed to mitigate off-target DNA cleavage of Cas12a. In this paper it also serves as a mechanistic probe for bridge-helix-mediated allosteric activation.; provides a bridge-helix perturbation variant for mechanistic dissection of Cas12a activation; addresses off-target DNA cleavage of Cas12a
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The variant was previously developed to mitigate off-target DNA cleavage of Cas12a. In this paper it also serves as a mechanistic probe for bridge-helix-mediated allosteric activation.
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provides a bridge-helix perturbation variant for mechanistic dissection of Cas12a activation
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addresses off-target DNA cleavage of Cas12a
Problem links
addresses off-target DNA cleavage of Cas12a
LiteratureThe variant was previously developed to mitigate off-target DNA cleavage of Cas12a. In this paper it also serves as a mechanistic probe for bridge-helix-mediated allosteric activation.
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The variant was previously developed to mitigate off-target DNA cleavage of Cas12a. In this paper it also serves as a mechanistic probe for bridge-helix-mediated allosteric activation.
provides a bridge-helix perturbation variant for mechanistic dissection of Cas12a activation
LiteratureThe variant was previously developed to mitigate off-target DNA cleavage of Cas12a. In this paper it also serves as a mechanistic probe for bridge-helix-mediated allosteric activation.
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The variant was previously developed to mitigate off-target DNA cleavage of Cas12a. In this paper it also serves as a mechanistic probe for bridge-helix-mediated allosteric activation.
Published Workflows
Objective: Understand the molecular mechanisms of bridge-helix-mediated activation of Cas12a for DNA cleavage using an engineered FnoCas12a bridge-helix variant.
Why it works: The abstract states that comparison of variant and wild-type structures, together with activity assays and computational simulations, establishes the mechanistic role of bridge-helix transitions in hybrid propagation and RuvC activation.
bridge-helix loop-to-helical transitionbridge-helix bendingRNA-DNA hybrid propagationlid loop-to-helical transitionRuvC active-site openingstructure determinationactivity assayscomputational simulationspairwise 3D structural comparison
Stages
- 1.Structural capture of FnoCas12aKD2P activation states(functional_characterization)
The study reports five structures of FnoCas12aKD2P at different activation states to define structural transitions associated with activation.
Selection: Capture different conformational activation states of the engineered variant.
- 2.Comparative structural and functional analysis against wild-type(secondary_characterization)
This stage integrates orthogonal evidence types to connect observed structural transitions to RNA-DNA hybrid propagation and RuvC activation.
Selection: Compare variant and wild-type structures together with activity assays and computational simulations to establish mechanism.
- 3.Cross-family 3D structural comparison(secondary_characterization)
The abstract states that pairwise 3D comparison provides insight into diversity of bridge-helix structural organization across mechanistically similar enzymes.
Selection: Compare bridge helix and RuvC organization across Cas12 and Cas9 families.
Taxonomy & Function
Primary hierarchy
Mechanism Branch
Architecture: A reusable architecture pattern for arranging parts into an engineered system.
Mechanisms
allosteric regulationconformational activationConformational UncagingPhotocleavager-loop formation controlruvc activation controlTechniques
No technique tags yet.
Target processes
No target processes tagged yet.
Implementation Constraints
cofactor dependency: cofactor requirement unknownencoding mode: genetically encodedimplementation constraint: context specific validationoperating role: actuatorswitch architecture: cleavageswitch architecture: uncaging
Use of this variant requires the engineered K969P and D970P substitutions in FnoCas12a. The abstract indicates that structural comparison, activity assays, and computational simulations were used to study it.; requires the K969P/D970P double substitutions in the bridge helix; mechanistic interpretation in this paper depends on comparison to wild-type structures, activity assays, and computational simulations
The abstract does not show that the variant solves all specificity or activity limitations of Cas12a in practical genome editing settings. It also does not provide delivery, cellular performance, or therapeutic-use details.; abstract does not quantify editing or cleavage performance; utility is described for mechanistic study and off-target mitigation, but implementation scope is not detailed in the abstract
Validation
Cell-freeBacteriaMammalianMouseHumanTherapeuticIndep. Replication
Supporting Sources
Ranked Claims
FnoCas12aKD2P was previously developed to mitigate off-target DNA cleavage of Cas12a.
To mitigate the off-target DNA cleavage of Cas12a, we previously developed a Francisella novicida Cas12a variant (FnoCas12a<KD2P>)
The study reports five structures of FnoCas12aKD2P at different states of conformational activation.
We report five structures of FnoCas12a<KD2P> that are at different states of conformational activation.
Approval Evidence
1 source2 linked approval claimsfirst-pass slug fnocas12akd2p
we previously developed a Francisella novicida Cas12a variant (FnoCas12a<KD2P>) by introducing double proline substitutions (K969P/D970P) in a conserved arginine-rich helix called the bridge helix (BH)
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engineering outcomesupports
FnoCas12aKD2P was previously developed to mitigate off-target DNA cleavage of Cas12a.
To mitigate the off-target DNA cleavage of Cas12a, we previously developed a Francisella novicida Cas12a variant (FnoCas12a<KD2P>)
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structural observationsupports
The study reports five structures of FnoCas12aKD2P at different states of conformational activation.
We report five structures of FnoCas12a<KD2P> that are at different states of conformational activation.
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Comparisons
Source-stated alternatives
The abstract directly contrasts the variant with wild-type FnoCas12a. It also references broader structural comparison across Cas12 and Cas9 families rather than naming another engineered specificity variant.
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The abstract directly contrasts the variant with wild-type FnoCas12a. It also references broader structural comparison across Cas12 and Cas9 families rather than naming another engineered specificity variant.
Source-backed strengths
explicitly engineered variant used across structural, activity, and computational analyses; captures different conformational activation states in reported structures
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explicitly engineered variant used across structural, activity, and computational analyses
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captures different conformational activation states in reported structures
Compared with CRISPR/Cas9
The abstract directly contrasts the variant with wild-type FnoCas12a. It also references broader structural comparison across Cas12 and Cas9 families rather than naming another engineered specificity variant.
Shared frame: source-stated alternative in extracted literature
Strengths here: explicitly engineered variant used across structural, activity, and computational analyses; captures different conformational activation states in reported structures.
Relative tradeoffs: abstract does not quantify editing or cleavage performance; utility is described for mechanistic study and off-target mitigation, but implementation scope is not detailed in the abstract.
Source:
The abstract directly contrasts the variant with wild-type FnoCas12a. It also references broader structural comparison across Cas12 and Cas9 families rather than naming another engineered specificity variant.
Compared with CRISPR/Cas9 system
The abstract directly contrasts the variant with wild-type FnoCas12a. It also references broader structural comparison across Cas12 and Cas9 families rather than naming another engineered specificity variant.
Shared frame: source-stated alternative in extracted literature
Strengths here: explicitly engineered variant used across structural, activity, and computational analyses; captures different conformational activation states in reported structures.
Relative tradeoffs: abstract does not quantify editing or cleavage performance; utility is described for mechanistic study and off-target mitigation, but implementation scope is not detailed in the abstract.
Source:
The abstract directly contrasts the variant with wild-type FnoCas12a. It also references broader structural comparison across Cas12 and Cas9 families rather than naming another engineered specificity variant.
Ranked Citations
- 1.