title: Lanthanide ion luminescence as a probe of DNA structure. 1. Guanine-containing oligomers and nucleotides.
abstract: Laser-induced Eu(3+) luminescence spectroscopy is used to probe the interaction of Eu(3+) ion with guanine-containing nucleotides and single-stranded oligomers. By using time-resolved and non-time-resolved Eu(3+) luminescence techniques, two classes of Eu(3+) binding site are observed in oligo(dG)10, oligo(dG)8, oligo(dG)6, oligo(dG)4, and d-GMP. One class of site binds Eu(3+) ions more strongly than the other. Since the "tight" class of bound Eu(3+) ions have two coordinated water molecules, it is inferred that six or seven atoms from the oligomers are coordinating the Eu(3+). The "weaker" class of Eu(3+) ion sites involve the coordination of six or seven water molecules and therefore, are coordinated by one or two atoms from the oligomer. The tight class of Eu(3+) binding site is attributed to an interstrand association of Eu(3+) with the oligomers forming dimeric or polymeric structures. The dissociation constants (Kd) for the 1:1 complexes Eu(d-GMP)+ and Eu(d-GTP)- have been determined as well as the Kd for the dimerization reaction of Eu(d-GMP)+. The Tb(3+) luminescence enhancement properties of these molecules are also examined in relation to their EU(3+) binding characteristics.
authors.affiliation: Department of Chemistry, Pennsylvania State University, University Park.
authors.forename: S L
authors.initials: SL
authors.lastname: Klakamp
authors.forename: W D
authors.initials: WD
authors.lastname: Horrocks
mesh_terms: D001665:Binding Sites; D004247:DNA / Q000737:chemistry*; D003848:Deoxyguanine Nucleotides / Q000737:chemistry*; D005063:Europium / Q000737:chemistry*; D008163:Luminescent Measurements; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D013057:Spectrum Analysis; D013725:Terbium / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D003848:Deoxyguanine Nucleotides; D009838:Oligodeoxyribonucleotides; C033538:oligodeoxyguanylic acid; D014867:Water; D013725:Terbium; D005063:Europium; C007257:2'-deoxyguanosine 5'-phosphate; D004247:DNA