The low affinity of peptide nucleic acid (PNA) to hybridize with DNA in the presence of a mismatch endows PNA with a high degree of discriminat-ory capacity that has been exploited in therapeutics for the selective inhibi-tion of the expression of point-mutated genes. To obtain a structural basis for this intriguing property, molecular dynamics simulations are carried out on PNAÆDNA duplexes formed at the Ki-ras proto-oncogene, compri-sing the point-mutated (GAT), and the corresponding wild-type (GGT) codon 12. .
