title: Molecular design of a pyrrole-imidazole hairpin polyamides for effective DNA alkylation.
abstract: New hairpin polyamide-CPI (CPI = cyclopropylpyrroloindole) conjugates, compounds 12-14, were synthesized and their DNA-alkylating activities compared with the previously prepared hairpin polyamide, compound 1, by high-resolution denaturing gel electrophoresis with 450 base pair (bp) DNA fragments and by HPLC product analysis of the synthetic decanucleotide. In accord with our previous results, alkylation by compound 1 occurred predominantly at the G moiety of the sequence 5'-AGTCAG-3' (site 3). However, compound 12, in which the structure of the alkylating moiety of compound 1 is replaced with segment A of duocarmycin A DU-86 (CPI), did not show any DNA alkylating activity. In clear contrast, the hairpin CPI conjugate 13, which differs from compound 1 in that it lacks one Py unit and possesses a vinyl linker, alkylated the A of 5'-AGTCAG-3' (site 3) efficiently at nanomolar concentrations. Alkylation by compound 14, which has a vinyl linker, occurred at the A of 5'-AGTCCA-3' (site 6) and at several minor alkylation sites, including mismatch alkylation at A of 5'-TCACAA-3' (site 2). The significantly different reactivity of the alkylating hairpin polyamides 1, 12, 13, and 14 was further confirmed by HPLC product analysis by using a synthetic decanucleotide. The results suggest that hairpin polyamide--CPI conjugate 13 alkylates effectively according to Dervan's pairing rule, and with a new mode of recognition in which the Im-vinyl linker (L) pair targets G-C base pairs. These results demonstrate that incorporation of the vinyl-linker pairing with Im dramatically improves the reactivity of hairpin polyamide--CPI conjugates.
authors.affiliation: Division of Biofunctional Molecules, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Surugadai, Kanda, Chiyoda, Tokyo 101-0062, Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Bando
authors.forename: Akihiko
authors.initials: A
authors.lastname: Narita
authors.forename: Isao
authors.initials: I
authors.lastname: Saito
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sugiyama
mesh_terms: D000478:Alkylation; D020029:Base Pairing; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000737:chemistry*; D015195:Drug Design; D007093:Imidazoles / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D009757:Nylons / Q000138:chemical synthesis*; D009841:Oligonucleotides / Q000138:chemical synthesis; D011758:Pyrroles / Q000737:chemistry*; D013696:Temperature
chemical_list: D007093:Imidazoles; D009757:Nylons; D009841:Oligonucleotides; D011758:Pyrroles; D004247:DNA