title: Isoguanine and 5-methyl-isocytosine bases, in vitro and in vivo.
abstract: The synthesis, base-pairing properties and in vitro and in vivo characteristics of 5-methyl-isocytosine (isoC(Me) ) and isoguanine (isoG) nucleosides, incorporated in an HNA(h) (hexitol nucleic acid)-DNA(d) mosaic backbone, are described. The required h-isoG phosphoramidite was prepared by a selective deamination as a key step. As demonstrated by Tm measurements the hexitol sugar showed slightly better mismatch discrimination against dT. The d-isoG base mispairing follows the order T>G>C while the h-isoG base mispairing follows the order G>C>T. The h- and d-isoC(Me) bases mainly mispair with G. Enzymatic incorporation experiments show that the hexitol backbone has a variable effect on selectivity. In the enzymatic assays, isoG misincorporates mainly with T, and isoC(Me) misincorporates mainly with A. Further analysis in vivo confirmed the patterns of base-pair interpretation for the deoxyribose and hexitol isoC(Me) /isoG bases in a cellular context, through incorporation of the bases into plasmidic DNA. Results in vivo demonstrated that mispairing and misincorporation was dependent on the backbone scaffold of the base, which indicates rational advances towards orthogonality.
authors: Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven (Belgium).
authors: Omprakash
authors: O
authors: Bande
authors: Rania
authors: R
authors: Abu El Asrar
authors: Darren
authors: D
authors: Braddick
authors: Shrinivas
authors: S
authors: Dumbre
authors: Valérie
authors: V
authors: Pezo
authors: Guy
authors: G
authors: Schepers
authors: Vitor B
authors: VB
authors: Pinheiro
authors: Eveline
authors: E
authors: Lescrinier
authors: Philipp
authors: P
authors: Holliger
authors: Philippe
authors: P
authors: Marlière
authors: Piet
authors: P
authors: Herdewijn
mesh_terms: D044503:5-Methylcytosine / Q000031:analogs & derivatives* / Q000737:chemistry; D006147:Guanine / Q000737:chemistry*; D015394:Molecular Structure; D009705:Nucleosides / Q000737:chemistry*
chemical_list: C412877:5-methyl isocytosine; D009705:Nucleosides; D006147:Guanine; D044503:5-Methylcytosine; C008183:isoguanine
keywords: HNA; XNA plasmid; isoG; nucleosides; polymerase