3'-End Nucleic Acid Labeling via Enzymatic Synthesis and Click Conjugation
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Solution Overview
Problem
Existing methods for labeling nucleic acids at the 3′-end are inefficient and limited by enzyme preferences, making them unsuitable for broad applications, particularly for single-stranded DNAs and requiring complex chemical modifications.
Innovation Solution
A method using a pair of functional moieties that covalently couple to introduce specific modifications or labels at the 3′-end of nucleic acids, employing Thermococcaceae DNA polymerases for template-independent enzymatic synthesis, followed by bioorthogonal reactions like click conjugation to stabilize the linkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional chemical methods are used for preparing labeled nucleic acids, then labeling can be achieved, but the process requires complicated chemical modifications and is tedious and inefficient
Solution Approach 1:
The patent replaces complex chemical modification methods with a biochemical approach using engineered DNA polymerases. The mechanical/chemical process of manual chemical modification is substituted by an enzymatic system that naturally performs the labeling function, thereby simplifying the manufacturing process while reducing complexity.
Solution Approach 2:
The patent introduces an intermediary enzyme system (engineered DNA polymerase) that mediates between the nucleic acid substrate and the label. This intermediary facilitates the transfer of labels to the 3'-end of nucleic acids through enzymatic activity, avoiding the need for direct complex chemical modifications.
2Adaptability or versatility
If TdT enzyme is used to add base-labeled nucleotide to 3'-end of ssDNA or blunt-end dsDNA, then labeling is possible, but the enzyme cannot efficiently utilize 3'-modified nucleotide for DNA elongation
Solution Approach 1:
The patent changes the parameters of the DNA polymerase enzyme through engineering modifications. The engineered polymerase has altered properties that enable it to efficiently incorporate 3'-modified nucleotides, unlike the natural TdT enzyme. This parameter change resolves the contradiction by maintaining versatility while improving productivity.
Solution Approach 2:
The patent uses a disposable engineered DNA polymerase system that is optimized for single-use labeling reactions. The enzyme is designed to perform its function efficiently in the labeling reaction without requiring long-term stability or reusability, allowing for optimized performance in each individual reaction.
3Adaptability or versatility
If Pol I or TdT enzymes are used for nucleic acid-labeling, then labeling can be performed, but the enzymes exhibit strong preference for certain types of modified nucleotides which restrains broader applications
Solution Approach 1:
The patent creates a universal engineered DNA polymerase that can handle multiple types of modified nucleotides. This multi-functional enzyme is designed to accept various label types and modifications at the 3'-end, making the labeling method universally applicable to different nucleic acid probe applications without being restricted by enzyme preferences.
Solution Approach 2:
Instead of adapting different enzymes to work with various modified nucleotides, the patent inverts the approach by engineering a single DNA polymerase to universally accept all types of modified nucleotides. This inversion of the traditional approach eliminates the need to match specific enzymes with specific nucleotide types.
4Manufacturing precision
If DNA nick translation is used to label DNA, then labeling of dsDNA is achieved, but the method cannot be used for labeling at the 5'-end or 3'-end of DNAs
Solution Approach 1:
The patent applies local quality by specifically targeting the 3'-end of nucleic acids for labeling. The engineered DNA polymerase is designed to act specifically at the 3'-end position, providing precise spatial control over where the label is incorporated. This local specificity enables versatile applications while maintaining manufacturing precision.
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
Enables efficient and versatile labeling of nucleic acids at the 3′-end, allowing for broader applications and improved nucleic acid probe utility in molecular biology and diagnostics.
Implementation Method 1
employing Thermococcaceae DNA polymerases for template-independent enzymatic synthesis
Implementation Method 2
followed by bioorthogonal reactions like click conjugation to stabilize the linkage
Data Source
AI summary
Provided is a method for introducing a modification to a 3′-end of a polynucleotide, including coupling a detectable label or a tag to the 3-end of the polynucleotide. Also provided is a kit for modifying a polynucleotide at the 3-end of the polynucleotide. The kit includes a polymerase, a nucleotide with a reactive moiety, and a desired molecule to be coupled to the nucleotide.