Probing of B-Z junctions in recombinant plasmids in vitro and in the cell with different osmium tetroxide complexes.
Complexes of OsO4 with 2,2'-bipyridine (Os,2,2'-bipy),4,4'-bipyridine (Os,4,4'-bipy), 1,10-phenanthroline (Os,phe), bathophenanthroline disulfonic acid (Os,bpds) and OsO4, pyridine reagent (Os,py) were used to probe structural distortions at the junctions between right-handed B and left-handed Z DNA in supercoiled plasmids pRW751 and pPK1 (both containing (dC-dG)13 and (dC-dG)16 segments). With all five complexes the site-specific modification at the B-Z junctions was detected in vitro but only Os,2,2'-bipy and Os,bpds produced strong site specific modification at submillimolar concentrations. In addition to the B-Z junctions. Os,phe also reacted at other sites. With the exception of Os,2,2'-bipy no one of the tested OsO4 complexes has proved to be suitable for probing structural distortions at the B-Z junctions in E. coli cells.
Boublíková
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P
Institute of Biophysics, Czechoslovak Academy of Sciences, Brno.
Palecek
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E
D004269:DNA, Bacterial; D004274:DNA, Recombinant; D004278:DNA, Superhelical; D004926:Escherichia coli / Q000235:genetics; D015335:Molecular Probes; D009690:Nucleic Acid Conformation; D009993:Osmium Tetroxide; D010957:Plasmids
D004269:DNA, Bacterial; D004274:DNA, Recombinant; D004278:DNA, Superhelical; D015335:Molecular Probes; D009993:Osmium Tetroxide