Sequence selective recognition of double-stranded RNA at physiologically relevant conditions using PNA-peptide...

Area of Science:

• Biochemistry
• Molecular Biology
• Oligonucleotide Chemistry

Background:

• Peptide nucleic acids (PNAs) are DNA mimics with potential for nucleic acid targeting.
• Enhancing PNA binding affinity and cellular uptake is crucial for therapeutic development.
• Triple helical binding to RNA offers a specific targeting mechanism.

Purpose of the Study:

• To investigate the effect of tetralysine peptide conjugation on PNA binding to RNA.
• To evaluate the sequence selectivity and affinity of PNA-peptide conjugates for double-stranded RNA (dsRNA) versus double-stranded DNA (dsDNA).
• To assess the cellular uptake of modified PNAs in HEK293 cells.

Main Methods:

• Synthesis of PNA hexamers and heptamers with cationic nucleobase and tetralysine modifications.
• Assessment of triple helical binding affinity to RNA under physiological conditions.
• Evaluation of binding selectivity for dsRNA over dsDNA.
• Cellular uptake studies using HEK293 cells.

Main Results:

• Conjugation of PNAs with tetralysine peptides significantly enhanced triple helical binding to RNA.
• PNA-peptide conjugates demonstrated high binding affinity and sequence selectivity for complementary dsRNA.
• These conjugates showed a strong preference for dsRNA, with minimal affinity for dsDNA.
• Cationic PNAs exhibited efficient cellular uptake, unlike unmodified PNAs.

Conclusions:

• Tetralysine peptide conjugation is an effective strategy to enhance PNA binding to dsRNA.
• PNA-peptide conjugates offer selective targeting of dsRNA with improved cellular internalization.
• These findings support the potential of PNA-peptide conjugates as therapeutic agents for RNA-targeting applications.