Triple helix formation inhibits DNA gyrase activity.
The goal of this work was to examine the effect of triple helix-forming oligonucleotides on a gyrase target region and on the activity of the enzyme. Using melting temperature measurements and gel mobility shift analysis, it was found that modified oligonucleotides can form a triple helix along the 29-nucleotide region of a 32-bp duplex representing part of the gyrase DNA-target sequence of the 162-bp fragment from pBR322. Triplex formation with this target region has been achieved at pH 7.5 by using a synthetic oligonucleotide in which cytosine was replaced by the C-nucleoside of 2-aminopyridine. The results of the enzymic experiments in vitro with the 162-bp fragment demonstrated that the cleavage reaction mediated by gyrase can be efficiently inhibited by the triplex-forming oligonucleotide modified with 2-aminopyridine. A possible inhibitory mechanism is discussed.
Simon
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H
Institut für Molekularbiologie, Friedrich-Schiller-Universität Jena, Germany.
Förtsch
I
I
Burckhardt
G
G
Gabrielyan
A
A
Birch-Hirschfeld
E
E
Stelzner
A
A
Prévot-Halter
I
I
Leumann
C
C
Zimmer
C
C
D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D010957:Plasmids / Q000235:genetics; D013302:Streptomyces / Q000201:enzymology; D013379:Substrate Specificity; D059005:Topoisomerase II Inhibitors
D009838:Oligodeoxyribonucleotides; D059005:Topoisomerase II Inhibitors; D004250:DNA Topoisomerases, Type II