title: Automated synthesis of 3'-metalated oligonucleotides.
abstract: We report the first synthesis of a metallonucleoside bound to a solid support and subsequent oligonucleotide synthesis with this precursor. Large-scale syntheses of metal-containing oligonucleotides are achieved using a solid support modified with [Ru(bpy)(2)(impy')](2+) (bpy is 2,2'-bipyridine; impy' is 2'-iminomethylpyridyl-2'-deoxyuridine). A duplex formed with the metal-containing oligonucleotide exhibits superior thermal stability when compared to the corresponding unmetalated duplex (T(m) = 50 degrees C vs T(m) = 48 degrees C). Electrochemical (E(1/2) = 1.3 V vs NHE), absorption (lambda(max) = 480 nm), and emission (lambda(max) = 720 nm, tau = 44 ns, Phi = 0.11 x 10(-)(3)) data for the ruthenium-modified oligonucleotides indicate that the presence of the oligonucleotide does not perturb the electronic properties of the ruthenium complex. The absence of any change in the emission properties upon duplex formation suggests that the [Ru(bpy)(2)(impy)](2+) chromophore will be a valuable probe for DNA-mediated electron-transfer studies. Despite the relatively high Ru(III/II) reduction potential, oxidative quenching of photoexcited [Ru(bpy)(2)(impy)](2+) does not lead to oxidative damage of guanine or other DNA bases.
authors.affiliation: Division of Biology and the Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: E S
authors.initials: ES
authors.lastname: Krider
authors.forename: J J
authors.initials: JJ
authors.lastname: Rack
authors.forename: N L
authors.initials: NL
authors.lastname: Frank
authors.forename: T J
authors.initials: TJ
authors.lastname: Meade
mesh_terms: D001483:Base Sequence; D001671:Biochemistry / Q000379:methods; D002384:Catalysis; D002852:Chromatography, Ion Exchange; D004247:DNA / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry; D015394:Molecular Structure; D009691:Nucleic Acid Denaturation; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis* / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010084:Oxidation-Reduction; D012428:Ruthenium / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013329:Structure-Activity Relationship
chemical_list: D009838:Oligodeoxyribonucleotides; D009942:Organometallic Compounds; D006147:Guanine; D012428:Ruthenium; D004247:DNA