Hyperactive AID and TET Enzymes for Precise Epigenetic Editing
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Solution Overview
Problem
Current AID and TET enzymes lack tailored functions for specific applications, such as enhanced deamination activity and controlled oxidation steps, which are essential for precise genetic editing and epigenetic modifications.
Innovation Solution
Development of fusion proteins with hyperactive deamination activity, including APOBEC3B and A3A domains, and mutant TET enzymes that stall oxidation at 5-hydroxymethylcytosine, enabling increased mutation rates in genomes and introducing specific epigenetic modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wild-type AID/APOBEC enzymes are used, then baseline deamination activity is maintained, but mutation rates are insufficient for enhanced genetic editing applications
Solution Approach 1:
The patent applies parameter changes by introducing specific amino acid mutations (e.g., AID E58A, APOBEC3A H192A/Y193A, APOBEC3B H192A/Y193A) that alter the catalytic activity parameters of the enzymes. These mutations enhance deamination rates while maintaining substrate specificity, resolving the contradiction between productivity and reliability.
Solution Approach 2:
The patent creates composite enzymatic systems by fusing AID or APOBEC catalytic domains with CRISPR guide RNA complexes. This composite approach combines the gene-editing specificity of CRISPR with the enhanced deamination activity of mutated AID/APOBEC enzymes, achieving both high mutation rates and maintained reliability.
2Adaptability or versatility
If TET enzymes allow complete oxidation to 5-carboxylcytosine, then full demethylation potential is achieved, but control over intermediate epigenetic modifications is lost
Solution Approach 1:
The patent applies dynamics by engineering TET enzymes with adjustable oxidation kinetics. Mutations in the TET catalytic domain allow the enzyme to be tuned between producing intermediate products (5-hydroxymethylcytosine, 5-formylcytosine) and proceeding to complete oxidation (5-carboxylcytosine), providing dynamic control over epigenetic modification outcomes.
Solution Approach 2:
The patent uses parameter changes by modifying TET enzyme amino acid sequences to alter oxidation rate parameters and product distribution. These mutations enable precise control over the oxidation pathway, allowing researchers to select desired epigenetic marks based on application requirements.
3Productivity
If APOBEC3B catalytic domain is used alone, then deamination activity is present, but fusion with A3A domain provides hyperactive function
Solution Approach 1:
The patent applies merging by fusing the APOBEC3B catalytic domain with the APOBEC3A domain to create a chimeric protein. This combination merges the complementary functional elements of both domains, producing hyperactive deamination activity that exceeds the sum of individual domain activities, while the fusion structure maintains sufficient stability and specificity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The hyperactive AID and TET enzymes facilitate enhanced mutation rates and precise epigenetic editing, overcoming limitations of wild-type enzymes in genetic and epigenetic applications, such as CRISPR-based gene editing and epigenome modification.
Implementation Method 1
These enzymes deaminate cytidine to uridine, leading to nucleotide changes in RNA and DNA that can alter function
Implementation Method 2
TET enzymes catalyze the oxidation of 5-methylcytosine (mC), the mainstay of the epigenome, into three additional bases: 5-hydroxymethylcytosine (hmC), 5-formylcytosine (fC), and 5-carboxylcytosine (caC)
Data Source
AI summary
The present invention includes mutant AID, APOBEC, and Tet enzymes with improved functions. In one aspect the invention provides APOBEC fusion proteins comprising hyperactive deamination activity. In another aspect, the invention provides AID mutant proteins comprising hyperactive deamination activity. In yet another aspect, the invention provides mutant Tet proteins capable of stalling oxidation at a 5-hydroxymethylcytosine (hmC).