Cas9 Enzyme Mutations Reducing Off-Target Effects
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Solution Overview
Problem
Current CRISPR-Cas systems face challenges in reducing off-target activity while maintaining or enhancing target activity, which is crucial for precise gene editing applications.
Innovation Solution
Engineered CRISPR enzymes with specific modifications, such as amino acid substitutions, are developed to alter their binding properties, kinetics, and specificity when complexed with guide RNAs, thereby reducing off-target binding and increasing target specificity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CRISPR-Cas systems are used for gene editing, then target locus modification capability is achieved, but off-target effects occur reducing precision
Solution Approach 1:
The patent applies parameter changes by modifying amino acid residues in the Cas9 enzyme (specifically positions K848, K855, K862, K866, and combinations thereof) to alter the enzyme's binding properties and kinetics. These parameter changes in the enzyme's structure directly reduce off-target binding while maintaining or enhancing target specificity, resolving the contradiction between editing capability and precision.
2Manufacturing precision
If CRISPR enzyme concentration is reduced to enhance specificity, then off-target activity decreases, but target activity also decreases
Solution Approach 1:
The patent modifies the Cas9 enzyme's parameters through specific amino acid substitutions that enhance its binding kinetics and affinity for target sequences. This allows the enzyme to maintain high target activity even at lower concentrations, thereby improving specificity without sacrificing productivity. The modified enzyme exhibits altered binding properties that favor target over off-target sites.
3Manufacturing precision
If guide RNA sequence is truncated to reduce off-target binding, then off-target activity decreases, but binding efficiency to target decreases
Solution Approach 1:
The patent changes the parameters of the Cas9 enzyme itself rather than modifying guide RNA length. The amino acid substitutions in Cas9 (at positions K848, K855, K862, K866) alter the enzyme's intrinsic binding properties and kinetics, enabling it to maintain high binding efficiency to target sequences while exhibiting reduced off-target binding, without requiring guide RNA truncation.
Data Source
AI summary
Disclosed and claimed are mutation(s) or modification(s) of the CRISPR enzyme, for example a Cas enzyme such as a Cas9, which obtain an improvement, for instance a reduction, as to off-target effects of a CRISPR-Cas or CRISPR-enzyme or CRISPR-Cas9 system or complex containing or including such a mutated or modified Cas or CRISPR enzyme or Cas9. Methods for making and using and uses of such mutated or modified Cas or CRISPR enzyme or Cas9 and systems or complexes containing the same and products from such methods and uses are also disclosed and claimed.