title: Binding of [Pt(1C3)(dien)](2+) to the duplex DNA oligonucleotide 5'-d(TGGCCA)-3': the effect of an appended positive charge on the orientation and location of anthraquinone intercalation.
abstract: The binding of a platinum intercalator complex [Pt(1C3)(dien)](2+) (1C3 = 1-[(3-aminopropyl)amino]-anthracene-9,10-dione, dien = 3-azapentane-1,5-diamine) to DNA and to the self-complementary oligonucleotide 5'-d(TGGCCA)-3' has been investigated by UV-visible spectrophotometry and 2D NMR spectroscopy, respectively. The uncomplexed anthraquinone, 1C3, has an apparent DNA binding constant of 1.4 x 10(4), similar to that of ethidium bromide. Addition of the coordinatively saturated {Pt(dien)} moiety increases the binding constant to 3.7 x 10(5) M(-1), showing the effect of the increased positive charge introduced by this moiety. Multiple binding modes are evident from the lack of isosbestic points in the titration spectra and the non-linear nature of the half-reciprocal plot used to calculate the binding constant. [Pt(1C3)(dien)](2+) forms a 2 : 1 adduct with 5'-d(TGGCCA)-3' and is shown by 2D NMR to intercalate primarily in the TG:CA base pairs at the ends of the oligonucleotide with the side chain and {Pt(dien)} situated in the minor groove.
authors.affiliation: School of Chemistry, The University of Sydney, NSW, 2006, Australia.
authors.forename: Renee M
authors.initials: RM
authors.lastname: Whan
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Messerle
authors.forename: Trevor W
authors.initials: TW
authors.lastname: Hambley
mesh_terms: D000880:Anthraquinones / Q000737:chemistry*; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D007364:Intercalating Agents / Q000737:chemistry* / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D009944:Organoplatinum Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D010984:Platinum / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000880:Anthraquinones; D007364:Intercalating Agents; D009838:Oligodeoxyribonucleotides; D009944:Organoplatinum Compounds; D010984:Platinum; D004247:DNA