SSB-assisted duplex invasion of preorganized PNA into double-stranded DNA

Peptide nucleic acids (PNAs) are DNA analogues with modified backbones in which the sugar-phosphate moiety is replaced by N-(2-aminoethyl)glycine. PNAs are extremely good structural mimics of the DNA strand and are able to form very stable duplex structures through the Watson–Crick rule. These duplexes are in general more stable than those formed by the corresponding DNA and, furthermore, PNAs are not enzymatically degraded. Therefore, PNAs are of interest in many areas of chemistry, biology, and medicine including drug discovery, genetic diagnostics, and molecular recognition. In order to improve the favorable binding properties of PNAs, various PNA derivatives with backbone modifications have been developed. One of the most studied modifications is the introduction of amino-acid-derived stereogenic centers within the PNA backbone, such as d-lysine a-PNA (KaPNA), l-alanine g-PNA (Ag-PNA), [6] l-serine g-PNA (Sg-PNA) [7]