Related Experiment Video
Updated: Jun 3, 2026
09:16
In Vitro Directed Evolution of a Restriction Endonuclease with More Stringent Specificity
Published on: March 25, 2020
A General Enzymatic Strategy for Site-Specific Incorporation of Modified Genetic Building Blocks Into DNA.
Raveena Raveena1,2, Bhavana Ramadas1,2, Sidney Becker1,2
1Max-Planck Institute of Molecular Physiology, Dortmund, Germany.
Summary
A new enzymatic method enables precise DNA synthesis with modified building blocks. This eco-friendly approach offers high fidelity and purity, overcoming limitations of current chemical methods for custom DNA sequences.
Area of Science:
- Biotechnology
- Synthetic Biology
- Molecular Biology
Background:
- Current methods for site-specific DNA modification are limited.
- Phosphoramidite chemistry is inefficient, error-prone, and generates toxic waste.
- Existing enzymatic methods are context-dependent and lack generalizability.
Purpose of the Study:
- To develop a general enzymatic strategy for site-specific DNA synthesis.
- To overcome the limitations of current chemical and enzymatic DNA synthesis methods.
- To enable routine, eco-friendly synthesis of long, modified DNA sequences.
Main Methods:
- Utilized template-dependent polymerases for nucleotide incorporation.
- Employed an enzymatic strategy for high-fidelity synthesis.
- Leveraged intrinsic error correction for product purity.
Main Results:
- Demonstrated a proof-of-concept for a general enzymatic DNA synthesis strategy.
- Achieved site-specific incorporation of modified nucleotides with high fidelity.
- Generated highly pure DNA products through inherent error correction.
Conclusions:
- The presented enzymatic approach offers a generalizable and eco-friendly alternative for DNA synthesis.
- This method has the potential for automation on DNA sequencers using Sequencing-by-Synthesis (SBS) technology.
- Enables routine synthesis of long, site-specifically modified DNA sequences, including gene fragments and promoters.
Related Concept Videos
02:53Conservative Site-specific Recombination and Phase Variation
Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...
The recognition sites for Cre recombinase called LoxP...
01:11Restriction Enzymes
Restriction enzymes are bacterial enzymes used to cut DNA in a sequence-specific manner. To cleave DNA, they bind to specific palindromic sequences called restriction sites. Such palindromic DNA sequences or inverted repeats are commonly found in regions of functional significance, such as the origin of replication, gene operator sites, and regions containing transcription termination signals.
The host bacteria protect their own genomic DNA from these enzymes by methylating these sites. Some...
The host bacteria protect their own genomic DNA from these enzymes by methylating these sites. Some...
01:54Base Excision Repair
One of the common DNA damages is the chemical alteration of single bases by alkylation, oxidation, or deamination. The altered bases cause mispairing and strand breakage during replication. This type of damage causes minimal change to the DNA double helix structure and can be repaired by the base excision repair (BER) pathways. BER corrects damaged DNA sequences by removing the damaged base and restoring the original base sequence using the complementary strand as a template.
The first step of...
The first step of...
02:31Homologous Recombination
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
01:05Maxam-Gilbert Sequencing
In the same year as the discovery of the Sanger sequencing method, another group of scientists, Allan Maxam and Walter Gilbert, demonstrated their chemical-cleavage method for DNA sequencing. The Maxam-Gilbert method relies on using different chemicals that can cleave the DNA sequence at specific sites, the separation of resulting DNA fragments of variable size using electrophoresis, and deciphering the DNA sequence from the resulting gel bands.
Challenges of the Maxam-Gilbert Method
The...
Challenges of the Maxam-Gilbert Method
The...
01:09Recombinant DNA
Overview