Convergent DNA synthesis: a non-enzymatic dimerization approach to circular oligodeoxynucleotides

Area of Science:

• Molecular Biology
• Synthetic Chemistry
• Oligonucleotide Synthesis

Background:

• Circular DNA molecules have unique properties and applications in biotechnology and research.
• Conventional methods for synthesizing circular DNA can be inefficient and complex.
• Developing novel, high-yield strategies for circular DNA construction is crucial.

Purpose of the Study:

• To report a novel convergent, non-enzymatic approach for constructing circular DNA oligonucleotides.
• To demonstrate the efficiency and yield of this new method using homodimerization and heterodimerization strategies.
• To compare the yield of the novel method with conventional circularization techniques.

Main Methods:

• A single-step, non-enzymatic chemical ligation using BrCN/imidazole/Ni2+.
• Utilizing a DNA template to form a triple helical complex, bringing reactive ends together.
• Employing homodimerization and heterodimerization strategies for circle construction.
• Synthesizing circular DNA molecules ranging from 34 to 74 nucleotides (nt) in size.

Main Results:

• Successfully constructed circular DNAs of 42, 58, and 74 nt using homodimerization.
• Successfully constructed circular 34mers using heterodimerization with different precursor lengths.
• Demonstrated preparative yields for a biologically active 34mer circle, showing higher yield than conventional cyclization.
• Achieved conversions of approximately 33-85% from precursors to circular product in six additional constructions.

Conclusions:

• The novel convergent strategy provides an efficient, single-step, non-enzymatic method for circular DNA synthesis.
• This approach offers competitive or superior yields compared to traditional circularization methods.
• Convergent strategies enable higher yields for medium and large DNA molecules than standard linear synthesis alone.