RESUMEN
Six unnatural nucleotides featuring fluorine-substituted phenyl nucleobase analogues have been synthesized, incorporated into DNA, and characterized in terms of the structure and replication properties of the self-pairs they form. Each unnatural self-pair is accommodated in B-form DNA without detectable structural perturbation, and all are thermally stable and selective to roughly the same degree. Furthermore, the efficiency of polymerase-mediated mispair synthesis is similar for each unnatural nucleotide in the template. In contrast, the efficiency of polymerase-mediated self-pair extension is highly dependent on the specific fluorine substitution pattern. The most promising unnatural base pair candidate of this series is the 3-fluorobenzene self-pair, which is replicated with reasonable efficiency and selectivity.
Asunto(s)
Emparejamiento Base , Replicación del ADN , ADN/química , ADN/metabolismo , Secuencia de Bases , Dicroismo Circular , ADN/genética , ADN Polimerasa Dirigida por ADN/metabolismo , Espectroscopía de Resonancia Magnética , Estructura Molecular , Polifosfatos/metabolismo , Moldes Genéticos , TermodinámicaRESUMEN
A novel conformationally constrained pyridazinone E(ag)-base PNA-monomer 2 capable of binding thymine in a triplex motif was designed and synthesised. A bis-PNA with the E(ag)-base incorporated in the Hoogsteen strand was hybridised with a complementary DNA. Thermal stability studies revealed an increase in T(m) (4.3 degrees C per mod.) compared to a no-base unit, but showed no improvement over a previously described unconstrained analogue (E, 1). Surprisingly, no significant difference was found in the thermodynamic parameters (DeltaH degrees, DeltaS degrees and DeltaG degrees ) for PNA-DNA triplex formation involving 2 or the unconstrained analogue 1.
Asunto(s)
Conformación de Ácido Nucleico , Ácidos Nucleicos de Péptidos/química , Piridazinas/química , Timina/química , Evaluación Preclínica de Medicamentos/métodos , Estructura Molecular , Ácidos Nucleicos de Péptidos/genética , TermodinámicaRESUMEN
To expand the triplex recognition repertoire of Nucleic Acids, novel nucleobases that recognize thymine in a T-A base pair are still required. A novel conformationally constrained PNA-monomer (II) capable of binding T in a triplex motif was designed and synthesized in 7 steps starting from commercially available dimethyl 2-oxoglutarate.
