Characterization of DNA, RNA and DNA/RNA duplexes containing an L-nucleotide

Area of Science:

• Molecular Biology
• Biochemistry
• Nucleic Acid Chemistry

Background:

• DNA and RNA are fundamental nucleic acids with distinct structures.
• L-nucleotides are unnatural isomers of natural D-nucleotides.
• Understanding the structural and thermal properties of modified nucleic acids is crucial for various applications.

Purpose of the Study:

• To investigate the structural and thermal properties of DNA and RNA duplexes containing L-nucleotide residues.
• To compare the effects of L-nucleotide incorporation on DNA/DNA, RNA/RNA, and DNA/RNA duplexes.
• To analyze the conformational changes induced by L-nucleotides using circular dichroism (CD) spectroscopy.

Main Methods:

• UV-melting experiments to determine duplex thermal stability (Tm values).
• Circular Dichroism (CD) spectroscopy to assess duplex conformation.
• Synthesis and characterization of nucleic acid duplexes containing L-nucleotide residues.

Main Results:

• Incorporation of L-nucleotides into DNA/DNA, DNA/RNA, and RNA/RNA duplexes reduced their Tm values.
• The reduction in Tm was more pronounced when L-nucleotides were incorporated into RNA strands compared to DNA strands.
• CD spectra indicated that DNA/DNA and RNA/RNA duplexes with L-nucleotides retained similar conformations to unmodified duplexes.
• Heterochiral DNA/RNA hybrid duplexes containing L-nucleotides exhibited significantly different CD spectra compared to homochiral counterparts.

Conclusions:

• L-nucleotides destabilize nucleic acid duplexes, with a greater impact on RNA.
• The conformational impact of L-nucleotides differs between homochiral and heterochiral DNA/RNA duplexes.
• These findings provide insights into the structural versatility and stability of modified nucleic acids.