title: Incorporation of methyl group on azobenzene for the effective photo-regulation of hybridization and suppression of thermal isomerization.
abstract: We have synthesized azobenzene-tethered DNAs and have successfully photo-regulated various DNA functions. In the present study, we synthesized azobenzenes substituted with methyl group for still more effective photo-regulation of DNA hybridization. In trans-form, mono substituted azobenzene at ortho position stabilized the DNA duplex more efficiently than the other mono-substituted ones. In contrast, melting temperature (T(m)) for 2-methylazobenzene was lower in cis-form. As a result, change of T(m) (DeltaT(m)) induced by trans-cis isomerization became larger than that of unmodified azobenzene. Furthermore, di-substituted azobenzene at both ortho positions exhibited even larger DeltaT(m). Quite interestingly, thermal cis-to-trans isomerization of this azobenzene was about 10-fold slower than that of unmodified one. Thus, introduction of methyl group at 2, 6 positions raised both photo-regulatory activity and thermal stability of cis-form.
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Nishioka
authors.forename: Hiromu
authors.initials: H
authors.lastname: Kashida
authors.forename: Makoto
authors.initials: M
authors.lastname: Komiyama
authors.forename: Xingguo
authors.initials: X
authors.lastname: Liang
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Asanuma
mesh_terms: D001391:Azo Compounds / Q000737:chemistry* / Q000528:radiation effects*; D004247:DNA / Q000737:chemistry*; D007536:Isomerism; D008745:Methylation; D009691:Nucleic Acid Denaturation; D009693:Nucleic Acid Hybridization / Q000528:radiation effects*; D010755:Organophosphates / Q000737:chemistry* / Q000528:radiation effects*; D010777:Photochemistry; D013696:Temperature
chemical_list: D001391:Azo Compounds; D010755:Organophosphates; D004247:DNA