Hiroyuki Asanuma

The duplex-forming activity of an oligonucleotide has been photoregulated by making use of the isomerization of an azobenzene moiety in the side chain. When the azobenzene moiety is isomerized from the trans form to the cis form upon photoirradiation, the melting temperature of the duplex between the oligonucleotide and its complementary counterpart is significantly lowered, and the duplex is largely dissociated into two single-stranded oligonucleotides (shown schematically).

A drop in melting point of 21.5°C is induced by the UV-photolytic trans→cis isomerization of the duplex formed between an oligonucleotide bearing two D-threoninol-tethered azobenzene moieties in the side chain and its complementary counterpart. On irradiation with visible light, the dissociated single-stranded oligonucleotides regenerate the duplex.

Photonen als Treibstoff: Über die Photoregulierung der topologischen Struktur eines DNAzym/RNA-Komplexes gelingt das vollständige An- und Ausschalten des RNA-Verdaus auf der Ebene eines einzelnen Moleküls. Die Schlüsselbestandteile des Photoschalters sind Azobenzoleinheiten. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note

A supra-photoswitch is designed for complete ON/OFF switching of DNA hybridization by light irradiation for the purpose of using DNA as a material for building nanostructures. Azobenzenes, attached to D-threoninols that function as scaffolds, are introduced into each DNA strand after every two natural nucleotides (in the form (NNX)n where N and X represent the natural nucleotide and the azobenzene moiety, respectively). Hybridization of these two modified strands forms a supra-photoswitch consis

Molecular recognition is becoming increasingly important in both research and industry (e. g. water purification). This review focuses on molecular imprinting with cyclodextrins—highly useful because of their hydrophilic exterior and hydrophobic cavity—including the very effective strategy adopted by the authors (see Figure): Several host species are assembled to form a tailor-made guest complex with extremely exclusive selectivity.

The duplex-forming activities of oligonucleotides can be photomodulated by incorporation of an azobenzene unit. Upon isomerizing the trans-azobenzene to the cis form by irradiation with UV light, the T(m) value of the duplex (with the complementary DNA) is lowered so that the duplex is dissociated. The duplex is formed again when the cis-azobenzene is converted to the trans-azobenzene by irradiation with visible light. The photoregulation is successful irrespective of the position of the azobenz

DNA seesaw: Photoswitchable azobenzenecarboxylic acid 1 reversibly photoisomerizes between the trans form and the thermally stable cis form upon irradiation with visible light. A photon-fueled DNA nanodevice that moves like a seesaw in response to irradiation with different wavelengths of light was made by modifying DNA oligonucleotides with a combination of 1 and a conventional azobenzene (see picture). Detailed facts of importance to specialist readers are published as ”Supporting Information”

Methyl Red H aggregate of predetermined size is successfully synthesized from the DNA conjugate involving multiple Methyl Red moieties in sequence. In the single stranded state, hypsochromicity monotonically increases with the number of incorporated dyes: the peak maximum of the conjugate involving six Methyl Reds appears at 415 nm, and the shift is as great as 69 nm (3435 cm(-)(1)) with respect to the monomeric transition. This large hypsochromicity accompanied by the narrowing of the band clea

A new foldamer, acyclic threoninol nucleic acid (aTNA), has been synthesized by tethering each of the genetic nucleobases A, G, C, and T to d-threoninol molecules, which were then incorporated as building blocks into a scaffold bearing phosphodiester linkages. We found that with its fully complementary strand in an antiparallel fashion, the aTNA oligomer forms an exceptionally stable duplex that is far more stable than corresponding DNA or RNA duplexes, even though single-stranded aTNA is rather

To test the molecular exciton theory for heterodimeric chromophores, various heterodimers and clusters, in which two different dyes were stacked alternately, were prepared by hybridizing two oligodeoxyribonucleotides (ODNs), each of which tethered a different dye on D-threoninol at the center of the strand. NMR analyses revealed that two different dyes from each strand were stacked antiparallel to each other in the duplex, and were located adjacent to the 5'-side of a natural nucleobase. The spe

H. Asanuma, M. Kakazu, M. Shibata and T. Hishiya, Chem. Commun., 1997, 1971 DOI: 10.1039/A704176D

The introduction of methyl groups into two ortho positions (2' and 6' positions) of the same benzene ring in an azobenzene remarkably raised both its photoregulation ability and the thermal stability of the cis-form.