ABSTRACT
Peptide nucleic acids (PNAs) are not oligonucleotides and not even DNA analogues, but rather DNA mimics. Chemically PNA is a pseudopeptide in which the individual nucleobase units are amino acids joined together by amide bonds (Figure 4.1) (Nielsen et al., 1991; Egholm et al., 1992). Therefore, although PNA is a very good structural mimic of DNA in terms of its ability to form stable and sequence-selective complexes with complementary DNA or RNA oligonucleotides, it has unique chemical and physicochemical properties (Hyrup and Nielsen, 1996; Good and Nielsen, 1997). These can be exploited advantageously for development of pharmaceuticals, but also limit the degree to
which results, such as bioavailability and pharmacokinetics, obtained with oligonucleotides or their close chemical analogues can be used in developing PNA.
