Efforts to expand the genetic alphabet: identification of a replicable unnatural DNA self-pair.

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.

Synthesis and evaluation of a conformationally constrained pyridazinone PNA-monomer for recognition of thymine in triple-helix structures.

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.

A novel PNA-monomer for recognition of thymine in triple-helix structures.

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.