title: The effect of universal fluorinated nucleobases on the catalytic activity of ribozymes.
abstract: Four fluoro modified universal nucleobases have been synthesized. The universal nucleobases 1 and 2, containing a 2,4-difluorobenzene as nucleobase and a 4,6-difluorobenzimidazole, respectively, were chemically incorporated into a selected hammerhead ribozyme sequence which has already been retrovirally expressed as an anti-HIV ribozyme to investigate their effect on the catalytic activity of the ribozymes. The substitution of the natural nucleosides with either 1 or 2 results only in a small decrease of the catalytic activity. The Km value for the monosubstituted ribozyme with a 2,4-difluorobenzene is 309 nM(-1), the corresponding kcat is 2.91 x 10(-3) min(-1). A disubstituted hammerhead ribozyme carrying one of each modification has also been synthesized. For a further stabilization of the ribozyme/substrate complex 2'-(beta-aminoethoxy) modified fluorinated nucleosides 15 and 16 have been developed.
authors.affiliation: Institute for Organic Chemistry and Chemical Biology, Johann-Wolfgang-Goethe University, Frankfurt am Main, Germany.
authors.forename: A E
authors.initials: AE
authors.lastname: Klöpffer
authors.forename: J W
authors.initials: JW
authors.lastname: Engels
mesh_terms: D001483:Base Sequence; D001562:Benzimidazoles; D002384:Catalysis; D005461:Fluorine; D005464:Fluorobenzenes; D007700:Kinetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D016337:RNA, Catalytic / Q000737:chemistry / Q000378:metabolism*; D012263:Ribonucleosides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D001562:Benzimidazoles; D005464:Fluorobenzenes; D016337:RNA, Catalytic; D012263:Ribonucleosides; D005461:Fluorine