Interactions between single-stranded DNA binding protein and oligonucleotide analogs with different backbone...

Area of Science:

• Molecular Biology
• Biochemistry
• Oligonucleotide Chemistry

Background:

• Chemical modification of oligonucleotide backbones is crucial for enhancing antisense effects.
• Altered backbone chemistry can influence interactions with cellular proteins, affecting biological activity.
• Single-strand binding protein (SSB) plays a vital role in DNA repair and replication.

Purpose of the Study:

• To investigate the binding affinity of oligonucleotides with different backbone chemistries to SSB.
• To determine how backbone modifications impact oligonucleotide-SSB interactions.
• To assess the role of backbone chemistry in the biological efficacy of antisense oligonucleotides.

Main Methods:

• Synthesized oligonucleotides with identical sequences but varied internucleoside linkages: phosphodiester (PO), phosphorothioate (PS), phosphorodithioate (PS2), and methylphosphonate (MP).
• Assessed the binding affinity of these modified oligonucleotides to SSB using biophysical methods.
• Evaluated the influence of oligonucleotide length and sequence on SSB binding.

Main Results:

• Phosphorothioate (PS) and phosphorodithioate (PS2) oligonucleotides exhibited higher binding affinity to SSB compared to phosphodiester (PO) oligonucleotides.
• Methylphosphonate (MP) oligonucleotides showed negligible binding to SSB at tested concentrations.
• Oligonucleotide length significantly influenced SSB binding, whereas sequence was a less critical factor.

Conclusions:

• Oligonucleotide backbone chemistry is a critical determinant of binding affinity to essential cellular proteins like SSB.
• These findings highlight the importance of considering backbone modifications when designing antisense oligonucleotides for therapeutic applications.
• Understanding these interactions can optimize the design of antisense agents for improved biological outcomes.