title: Beyond A, C, G and T: augmenting nature's alphabet.
abstract: Efforts to expand the genetic alphabet are predicated upon a stable and replicable third base pair. Recent progress has resulted in the development of several candidates that are both stable in duplex DNA and replicated by DNA polymerases with various degrees of efficiency and fidelity. The candidate base pairs draw upon unnatural hydrogen-bonding topologies as well as upon shape complementarity and hydrophobic forces. This review provides a critical comparison of the third base pair candidates and discusses the further work required to expand the genetic alphabet.
authors.affiliation: Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, Maildrop CVN22, La Jolla, CA 92037, USA.
authors.forename: Allison A
authors.initials: AA
authors.lastname: Henry
authors.forename: Floyd E
authors.initials: FE
authors.lastname: Romesberg
mesh_terms: D020029:Base Pairing; D004247:DNA / Q000737:chemistry / Q000235:genetics*; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure
chemical_list: D004247:DNA; D004259:DNA-Directed DNA Polymerase