Highly selective single nucleotide polymorphism recognition by a chiral (5S) PNA beacon.
A chiral peptide nucleic acid (PNA) beacon containing a C-5 modified monomer based on L-lysine was synthesized. The terminal amino group of the lysine side chain was linked to a spacer for future applications on surfaces. The PNA beacon bears a carboxyfluorescein fluorophore and a dabcyl quencher at opposite ends. The DNA binding properties were compared with those of a homologous PNA beacon containing only achiral monomers. Both beacons underwent a fluorescence increase in the presence of complementary DNA, with higher efficiency and higher selectivity (evaluated using single mismatched DNA sequences) observed for the chiral monomer containing PNA. Ion exchange (IE) HPLC with fluorimetric detection was used in combination with the beacon for the selective detection of complementary DNA. A fluorescent peak corresponding to the PNA beacon:DNA duplex was observed at a very low detection limit (1 nM). The discriminating capacity of the chiral PNA beacon for a single mismatch was found to be superior to those observed with the unmodified one, thus confirming the potency of chirality for increasing the affinity and specificity of DNA recognition.
Totsingan
Filbert
F
Dipartimento di Chimica Organica e Industriale Università di Parma, 43100 Parma, Italy.
Tedeschi
Tullia
T
Sforza
Stefano
S
Corradini
Roberto
R
Marchelli
Rosangela
R
D020137:Base Pair Mismatch; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004247:DNA / Q000032:analysis* / Q000235:genetics* / Q000378:metabolism; D005453:Fluorescence; D009691:Nucleic Acid Denaturation; D020135:Peptide Nucleic Acids / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism; D013379:Substrate Specificity; D044366:Transition Temperature
D020135:Peptide Nucleic Acids; D004247:DNA