Sequence-specific cleavage of single-stranded DNA: oligodeoxynucleotide-EDTA X Fe(II)

Area of Science:

• Molecular Biology
• Biochemistry
• Synthetic Chemistry

Background:

• DNA probes are essential tools in molecular biology.
• Controlling DNA cleavage at specific sites remains a challenge.

Purpose of the Study:

• To synthesize and characterize a novel DNA hybridization probe functionalized with a metal chelator.
• To evaluate the sequence-specific DNA cleavage activity of the synthesized probe.

Main Methods:

• Synthesis of a 19-nucleotide DNA probe (DNA-EDTA 1) incorporating EDTA at the C-5 position of thymidine.
• Hybridization of the probe to a complementary sequence in a heat-denatured plasmid pBR322 restriction fragment.
• Induction of DNA cleavage using Fe(II), O2, and dithiothreitol under controlled conditions (25°C, pH 7.4).

Main Results:

• DNA-EDTA 1 specifically cleaved the complementary 19-nucleotide sequence within a 167-base-pair fragment.
• Cleavage occurred over a 16-nucleotide range at the hybridization site, attributed to a diffusible reactive species.
• No off-target cleavage was observed in the restriction fragment.

Conclusions:

• A novel method for synthesizing DNA-EDTA probes using phosphoramidite chemistry is established.
• The DNA-EDTA X Fe(II) system enables controlled, sequence-specific cleavage of single-stranded DNA and potentially RNA under mild conditions.
• These probes offer a promising tool for targeted nucleic acid manipulation.