TdT Variant Mutations Enhance DNA Synthesis Accuracy
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Solution Overview
Problem
Current template-free polymerases used in enzymatic DNA synthesis face challenges in incorporating desired nucleotides, particularly when primers have hairpin structures, leading to errors such as deletions, insertions, and substitutions, which affect DNA quality.
Innovation Solution
Development of novel TdT variants with specific amino acid substitutions or replacements at defined positions, which enhance the enzyme's ability to accurately incorporate nucleotides and reduce misincorporations during DNA synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If template-free polymerases are used for enzymatic DNA synthesis, then synthesis rate and efficiency are improved, but misincorporation errors (deletions, insertions, substitutions) increase particularly when primers have hairpin structures
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of the TdT enzyme through specific substitutions (e.g., E294Q, N295K, R296Q) to alter the enzyme's catalytic properties. These parameter changes in the enzyme's structure enable it to maintain high synthesis rates while significantly reducing misincorporation errors, particularly for primers with hairpin structures, thus resolving the contradiction between productivity and manufacturing precision.
2Ease of manufacture
If chemically-based synthesis methods are used for gene synthesis, then ease of manufacture is improved, but genetic error probability increases (0.5% per nucleotide)
Solution Approach 1:
The patent replaces the chemical-based synthesis mechanism with an enzymatic mechanism using engineered TdT variants. This substitution of the synthesis system from chemical to biological enables the process to maintain ease of manufacture while dramatically reducing genetic error rates, as the enzymatic method inherently provides higher fidelity in nucleotide incorporation compared to chemical synthesis.
3Manufacturing precision
If reversibly blocked nucleoside triphosphates are used in template-free polymerase synthesis, then sequence control is improved, but incorporation efficiency decreases
Solution Approach 1:
The patent modifies the enzyme's parameters through amino acid substitutions that enhance its ability to accommodate and incorporate reversibly blocked nucleoside triphosphates. The engineered TdT variants have altered catalytic parameters that allow them to maintain high incorporation efficiency while preserving the sequence control benefits of using blocked nucleotides, thus resolving the contradiction between precision and productivity.
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 novel TdT variants demonstrate improved DNA synthesis quality by reducing deletion, insertion, and substitution errors, resulting in more accurate and reliable nucleic acid synthesis.
Implementation Method 1
template-free polymerases, such as, terminal deoxynucleotidyl transferase (TdT)... enzymatically-based methods using template-free polymerases
Implementation Method 2
terminal deoxynucleotidyl transferase (TdT)... incorporate such modified nucleoside triphosphates... synthesizing a polynucleotide
Data Source
AI summary
The invention states to a novel DNA polymerase of the polX family, in particular a Terminal deoxynucleotidyl Transferase (TdT) variants comprising specific mutations or substitutions and their uses.