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Satoshi Obika

Publications and source records attributed to Satoshi Obika.

41 records · Page 3Linked to original sources
PubMed2002

Binding of threading intercalator to nucleic acids: thermodynamic analyses.

The constant melting temperature upon the change in the oligonucleotide concentration showed that the oligonucleotide d(CGCTTTGCG) formed a intramolecular hairpin rather than a duplex with an internal loop. We examined the thermodynamic properties of the interaction between the threading intercalator, naphthalene diimides designated as NDI, and a series of hairpin oligonucleotides, d(CGCTnGCG) (n = 3, 4, 5, and 6) designated as CGCn. A complex with a molar ratio of 1:1 was formed between NDI and CGCn. Because the observed negative entropy change was unfavorable for the binding of NDI to CGCn, the binding was driven by the large negative enthalpy change. All of the thermodynamic parameters for the threading intercalation were not significantly changed by the difference in the loop length n. The stem region rather than the loop region of CGCn is mainly involved in the binding of NDI.

Intercalating Agents↗
PubMed2002

[Down-regulation of a gene-expression by an antisense BNA oligonucleotide].

We recently developed a novel nucleic acid analogue, Bridged Nucleic Acid (BNA), one of the most promising artificial nucleic acids for antisense and/or antigene methodology. The antisense effects of BNA modified oligonucleotides targeting the Internal Ribosomal Entry Site (IRES) in Hepatitis C Virus (HCV) RNA were evaluated. As a result, it was found that the antisense BNA oligonucleotides efficiently suppressed the targeted gene-expression in a sequence specific manner. Although the stem region in the mRNA is generally thought to be out of target for the antisense strategy, BNA oligonucleotide targeting the stem region in the HCV-IRES gave a positive antisense effect, also. It is quite noteworthy.

Down-Regulation↗
PubMedDate not supplied

Triplex formation involving 2'-O,4'-C-methylene bridged nucleic acid (2',4'-BNA) with 2-pyridone base analogue: efficient and selective recognition of C:G interruption.

For the effective recognition of C:G interruption in homopurine-homopyrimidine duplex DNA, we examined triplex-forming ability and sequence-selectivity of a triplex-forming oligonucleotide (TFO) involving of 2'-O,4'-C-methylene bridged nucleic acid with 2-pyridone base analogue. We found that the modified TFO formed stable triplex with high binding affinity and sequence-selectivity.

Base Pairing↗
PubMedDate not supplied

Triplex formation involving 2'-O,4'-C-methylene bridged nucleic acid (2',4'-BNA) with 1-isoquinolone base analogue: efficient and selective recognition of C:G interruption.

For the effective recognition of C x G interruption in homopurine-homopyrimidine duplex DNA, we examined triplex-forming ability and sequence-selectivity of a triplex-forming oligonucleotide (TFO) involving of 2'-O, 4'-C-methylene bridged nucleic acid with 1-isoquinolone base analogue. We found that the modified TFO formed stable triplex with high binding affinity and sequence-selectivity.

Base Pairing↗