title: Molecular design for reversing the photoswitching mode of turning ON and OFF DNA hybridization.
abstract: A new photoswitch for DNA hybridization involving para-substituted azobenzenes (such as isopropyl- or tert-butyl-substituted derivatives) with L-threoninol as a linker was synthesized. Irradiation of the modified DNA with visible light led to dissociation of the duplex owing to the destabilization effect of the bulky substituent on the trans-azobenzene. In contrast, trans-to-cis isomerization (UV light irradiation) facilitated duplex formation. The direction of this photoswitching mode was entirely reversed relative to the previous system with an unmodified azobenzene on D-threoninol whose trans form turned on the hybridization, and cis form turned it off. Such reversed and reversible photoswitching of DNA hybridization was directly demonstrated by using fluorophore- and quencher-attached oligonucleotides. Furthermore, it was revealed that the cis-to-trans thermal isomerization was greatly suppressed in the presence of the complementary strand owing to the formation of the more-stable duplex in the cis form.
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan, Fax: (+81) 52-789-2528.
authors.forename: Xingguo
authors.initials: X
authors.lastname: Liang
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan, Fax: (+81) 52-789-2528.
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Takenaka
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan, Fax: (+81) 52-789-2528.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Nishioka
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan, Fax: (+81) 52-789-2528.|Core Research for Evolution Science and Technology (CREST), Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Asanuma
mesh_terms: D001391:Azo Compounds / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D007536:Isomerism; D009693:Nucleic Acid Hybridization; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: D001391:Azo Compounds; D004247:DNA; C009850:azobenzene