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Enhanced strand invasion by peptide nucleic acid-peptide conjugates
Kunihiro Kaihatsu1, Dwaine A Braasch, Ahmet Cansizoglu
1Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9041, USA.
Biochemistry
|September 11, 2002
Summary
Synthetic molecules mimic DNA-binding proteins for enhanced gene targeting. Conjugates of peptide nucleic acids (PNAs) and peptides show 100-fold faster DNA strand invasion, enabling precise genetic analysis.
Area of Science:
- Biochemistry
- Molecular Biology
- Synthetic Chemistry
Background:
- Proteins efficiently recognize DNA through sequence-specific and non-selective electrostatic interactions.
- Synthetic molecules that mimic these protein functions could improve access to chromosome sequences for probes.
Purpose of the Study:
- To create synthetic molecules that combine specific DNA recognition with rapid targeting.
- To develop peptide-nucleic acid conjugates for enhanced DNA strand invasion.
Main Methods:
- Conjugates of bis-peptide nucleic acids (bisPNAs) and peptides were designed.
- Peptide design was based on the cationic DNA-binding protein staphylococcal nuclease.
- Rates of strand invasion by bisPNA-peptide conjugates were measured.
Main Results:
- Attachment of designed peptides increased DNA strand invasion rates by 100-fold compared to unmodified bisPNAs.
- Conjugates with D-amino acid peptides demonstrated stability in cellular extracts and were sensitive to single DNA mismatches.
- Efficient binding occurred across a broad range of pH, temperatures (0-65°C), and salt concentrations.
Conclusions:
- Peptide-PNA conjugates can mimic the rapid and selective binding of native DNA-binding proteins.
- Enhanced strand invasion over diverse conditions expands the utility of PNAs for genetic applications.