title: Triplex formation involving 2',4'-BNA with isoquinolone base analogue: efficient and selective recognition of C:G interruption.
abstract: We examined the thermodynamic properties of 2',4'-bridged nucleic acid containing 1-isoquinolone as a nucleobase (QB) to recognize a C interruption in the homopurine strand of the target duplex for pyrimidine motif triplex formation at neutral pH. The triplex formation involving triplex-forming oligonucleotide with QB is highly sequence-selective to specifically recognize C:G target base pair rather than the other G:C, T:A, or A:T base pairs. QB.C:G triad gives significantly larger binding constant than T.C:G triad, which has been known to be the most stable combination in natural base.C:G triad. Our results certainly support the idea that QB could be a key nucleoside to recognize a C interruption in the homopurine strand of the target duplex with high binding affinity and selectivity, and reduce the restriction of target sequences for triplex formation.
authors.affiliation: Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Torigoe
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Hari
authors.forename: Satoshi
authors.initials: S
authors.lastname: Obika
authors.forename: Takeshi
authors.initials: T
authors.lastname: Imanishi
mesh_terms: D001483:Base Sequence; D003596:Cytosine / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry*; D007546:Isoquinolines / Q000737:chemistry*; D009696:Nucleic Acids / Q000737:chemistry*
chemical_list: D007546:Isoquinolines; D009696:Nucleic Acids; D006147:Guanine; D003596:Cytosine