"Difficult" deoxyribonucleotide sequences in the solid-phase synthesis by the phosphoramidite chemistry

Area of Science:

• Oligonucleotide Synthesis
• Chemical Biology
• Biochemistry

Background:

• Solid-phase synthesis is a cornerstone for producing synthetic oligonucleotides.
• Optimizing synthesis conditions is crucial for maximizing the yield of full-length products.
• Sequence-dependent variations in yield can complicate oligonucleotide production.

Purpose of the Study:

• To catalog oligonucleotide sequences and compositions based on synthesis yield.
• To identify sequence features that negatively impact the yield of full-length oligonucleotides.
• To understand the chemical basis for yield variations in oligonucleotide synthesis.

Main Methods:

• Synthesized 76 oligonucleotide sequences with varying dinucleotide and trinucleotide repeats using phosphoramidite chemistry.
• Analyzed fully-deprotected products via denaturing anion-exchange High-Performance Liquid Chromatography (HPLC).
• Correlated sequence composition with the overall yield of full-length product.

Main Results:

• Oligonucleotides rich in 2 eal-deoxyadenosine residues yielded lower amounts of full-length product.
• Depurination of 2 eal-deoxyadenosine during detritylation is a likely cause for reduced yields.
• Specific dinucleotide steps, including d(CG)/d(GC) and d(AG)/d(GA), were associated with decreased full-length product yields.

Conclusions:

• Sequence composition significantly influences oligonucleotide synthesis efficiency.
• 2 eal-deoxyadenosine content and certain dinucleotide steps are critical factors affecting yield.
• Understanding these sequence-dependent effects can guide strategies for improved oligonucleotide synthesis and design.