title: Faithful PCR Amplification of an Unnatural Base-Pair Analogue with Four Hydrogen Bonds.
abstract: In vitro replication of an unnatural imidazopyridopyridine:naphthyridine base pair, (i.e., ImN(N):NaO(O)), having four hydrogen bonds was investigated. Kinetic studies of single-nucleotide insertion revealed that ImN(N) and NaO(O) were recognized as complementary bases by an exonuclease-deficient Klenow fragment with higher specificity and efficiency than two previously described pairs (ImN(O):NaO(N) and ImO(N):NaN(O)) because of higher thermal and thermodynamic stabilities and the DAAD:ADDA (D=donor, A=acceptor) hydrogen-bonding pattern of the ImN(N):NaO(O) pair. Faithful polymerase chain reaction (PCR) amplification of a DNA fragment containing the ImN(N):NaO(O) pair was achieved by using DNA polymerases possessing 3'→5' exonuclease activity (≈99.5 % per doubling).
authors.affiliation: Graduate School of Pharmaceutical Sciences, Tokushima University, Shomachi 1-78-1, Tokushima 770-8505 (Japan).
authors.forename: Noriko
authors.initials: N
authors.lastname: Tarashima
authors.affiliation: Biological Resources Institute, National Institute of Advanced Industrial Science and Technology 2-17-2-1, Tsukisamu-Higashi, Toyohira-ku, Sapporo 062-8517 (Japan).
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Komatsu
authors.affiliation: Graduate School of Pharmaceutical Sciences, Tokushima University, Shomachi 1-78-1, Tokushima 770-8505 (Japan).
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Furukawa
authors.affiliation: Graduate School of Pharmaceutical Sciences, Tokushima University, Shomachi 1-78-1, Tokushima 770-8505 (Japan). minakawa@tokushima-u.ac.jp.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Minakawa
mesh_terms: D020029:Base Pairing; D001483:Base Sequence; D004247:DNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004256:DNA Polymerase I / Q000378:metabolism; D006860:Hydrogen Bonding; D007093:Imidazoles / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D009287:Naphthyridines / Q000737:chemistry* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011725:Pyridines / Q000737:chemistry* / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D007093:Imidazoles; D009287:Naphthyridines; D011725:Pyridines; D004247:DNA; D004256:DNA Polymerase I
keywords: hydrogen bonds; imidazopyridopyrimidines; naphthyridines; polymerase chain reaction; unnatural base pairs