Book of Abstracts: Albany 2003
June 17-21 2003
Double-duplex Invasion of Pseudocomplementary Peptide Nucleic Acids into Duplex DNA at Elevated Salt Concentration
Synthetic reagents, which are capable of sequence-specific targeting of double-stranded DNA (dsDNA), are of significant interest in various fields of molecular biotechnology as they may provide tools for highly selective, nondenaturing manipulation with designated DNA sequences. In this connection, peptide nucleic acids (PNA) represent one of the most promising oligonucleotide mimics with unique physicochemical and biochemical characteristics. When adenines and thymines in two mutually complementary mixed-base PNA oligomers are substituted with diaminopurines and thiouracils, respectively, so-called pseudo-complementary PNAs (pcPNAs) are created. Pairs of pcPNAs efficiently target essentially any designated site on dsDNA by forming very stable PNA?DNA strand-displacement complexes via double-duplex invasion. One of the characteristic features of interaction between PNAs and dsDNA consists in strong inhibition of double helix invasion at high ionic strength (e.g. physiological conditions). To overcome this limitation we introduced a nick (single-stranded break) in dsDNA near the pcPNA target site. The results will be presented concerning the effect of salt concentration on the kinetics of pcPNA binding to dsDNA depending on the distance between the nick and the pcPNA binding site.
Center for Advanced Biotechnology