The orientations of the symmetrical third strands (G3A4G3) and (G3T4G3) within the triplexes (C3T4C3) - (G3A4G3) x (G3A4G3) and (C3T4C3) - (G3A4G3) x (G3T4G3) were investigated by fluorescence spectroscopy and thermal denaturation using pyrene-labeled oligodeoxynucleotides. In the two triplex structures, both parallel and antiparallel orientations of the third strand with respects to the purine Watson-Crick one were identified by means of pyrene excimer formation. The pyrene labels do not modify the melting temperature of the (C3T4C3) - (G3A4G3) x (G3T4G3) triplex but somewhat stabilize the corresponding duplex against thermal denaturation. The absorption melting profiles of the (C3T4C3) - (G3A4G3) x (G3A4G3) triplex are monophasic in agreement with previous reports. In contrast, the melting of this structure, when monitored by the pyrene excimer band, reveals a biphasic behavior. These data, together with kinetics measurements, strongly suggest exchange mechanisms between the homologous oligomers (G3A4G3), Hoogsteen, and Watson-Crick strands.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/bi971710t | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Antitumor polycyclic acridines. Part 16. Triplex DNA as a target for DNA-binding polycyclic acridine derivatives.
Oncol Res
October 2005
Cancer Research UK Experimental Cancer Chemotherapy Research Group, Centre for Bio-molecular Sciences, School of Pharmacy, University of Nottingham, Nottingham, NG7 2RD, UK.
Triple-stranded DNA structures have been implicated in a number of major biological processes, including the transcription and translation of a number of genes, as well as in the interaction of DNA with a number of proteins. Furthermore, antigene therapies under development are based on the recognition and binding of a single oligonucleotide strand to a double-stranded sequence, thus forming a triple helix. Triplex DNA formation is a relatively weak and temporary phenomenon; therefore, molecules that selectively bind to and stabilize triple helices may show a variety of novel biological effects.
View Article and Find Full Text PDFTriple helix formation and homologous strand exchange in pyrene-labeled oligonucleotides.
Biochemistry
December 1997
Laboratoire de Spectroscopie Biomoléculaire, URA CNRS 1430, UFR de Médecine et Biologie Humaine, Université Paris XIII, Bobigny, France.
The orientations of the symmetrical third strands (G3A4G3) and (G3T4G3) within the triplexes (C3T4C3) - (G3A4G3) x (G3A4G3) and (C3T4C3) - (G3A4G3) x (G3T4G3) were investigated by fluorescence spectroscopy and thermal denaturation using pyrene-labeled oligodeoxynucleotides. In the two triplex structures, both parallel and antiparallel orientations of the third strand with respects to the purine Watson-Crick one were identified by means of pyrene excimer formation. The pyrene labels do not modify the melting temperature of the (C3T4C3) - (G3A4G3) x (G3T4G3) triplex but somewhat stabilize the corresponding duplex against thermal denaturation.
View Article and Find Full Text PDFStudies on formation and stability of the d[G(AG)5]* d[G(AG)5]. d[C(TC)5] and d[G(TG)5]* d[G(AG)5]. d[C(TC)5] triple helices.
Biopolymers
April 1997
Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco 94143-0446, USA.
We have targeted the d[G(AG)5]. d[C(TC)5] duplex for triplex formation at neutral pH with either d[G(AG)5] or d[G(TG)5]. Using a combination of gel electrophoresis, uv and CD spectra, mixing and melting curves, along with DNase I digestion studies, we have investigated the stability of the 2:1 pur*pur.
View Article and Find Full Text PDFCalorimetric analysis of triple helices targeted to the d(G3A4G3).d(C3T4C3) duplex.
Biochemistry
August 1996
Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco 94143, USA.
We present a thermodynamic analysis based on differential scanning calorimetry (DSC) of three short intermolecular DNA triplexes targeted to the same DNA duplex: d(C+3T4C+3)*d- (G3A4G3).d(C3T4C3) (PYR), d(G3A4G3)*d(G3A4G3).d(C3T4C3) (PUR), and d(G3T4G3)*d(G3A4G3).
View Article and Find Full Text PDFPhysicochemical studies of the d(G3T4G3)*d(G3A4G3).d(C3T4C3) triple helix.
J Biol Chem
March 1995
Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco 94143, USA.
We have targeted the d(G3A4G3).d(C3T4C3) duplex for triplex formation with d(G3T4G3) in the presence of MgCl2. The resulting triple helix, d(G3T4G3)*d(G3-A4G3).
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!