Methods for the characterization of phosphatase-stabilized 2-5A-antisense chimeras

Area of Science:

• Oligonucleotide chemistry
• Analytical chemistry

Background:

• Antisense oligonucleotide (ASO) therapies require precise chemical modifications for stability and efficacy.
• 5'-monothiophosphate capping is a strategy to enhance resistance to nucleases.
• Quantifying the degree of thiolation is crucial for characterizing these modified ASOs.

Purpose of the Study:

• To develop and validate analytical methods for determining the thiolation degree in 5'-monothiophosphate-capped 2-5A-antisense chimeras.
• To investigate the reactivity of the 5'-monothiophosphate moiety with specific reporter reagents.
• To understand the influence of oligonucleotide backbone charge on thiolation reactions.

Main Methods:

• Development of chromatographic and spectrophotometric assays.
• Utilizing reporter reagents like 5-iodoacetomidofluorescein and 5,5'-dithiobis(2-nitrobenzoic acid).
• Conducting kinetic experiments to study reaction mechanisms.

Main Results:

• Established assays for quantifying thiolation in 5'-monothiophosphate-capped 2-5A-antisense chimeras.
• Demonstrated the utility of reporter reagents for analyzing these functionalized chimeras.
• Kinetic data indicated that oligonucleotide backbone negative charge impedes mixed disulfide formation with 5,5'-dithiobis(2-nitrobenzoic acid).

Conclusions:

• Validated chromatographic and spectrophotometric methods for assessing thiolation in modified antisense oligonucleotides.
• The developed assays facilitate the characterization of 5'-monothiophosphate-functionalized 2-5A-antisense chimeras.
• Oligonucleotide backbone charge significantly influences the kinetics of reactions involving the 5'-monothiophosphate group.