Viewing of complex molecules of ethidium bromide and plasmid DNA in solution by atomic force microscopy.
Tertiary structure changes in plasmid DNA, induced by ethidium bromide intercalation, have been observed in aqueous solutions by the use of an atomic force microscope. A relaxed closed circular pBR322 molecule became a positively supercoiled complex on the drug binding. The supercoiling always resulted in an interwound (or a plectonemic) form, but never a solenoidal (or a toroidal) form. A quantitative analysis of the compactness of such supercoiled complexes has been carried out.
Utsuno
K
K
High-tech Research Center, College of Science and Engineering, Iwaki Meisei University, Fukushima, Japan.
Tsuboi
M
M
Katsumata
S
S
Iwamoto
T
T
D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure*; D004591:Electrophoresis, Polyacrylamide Gel; D004996:Ethidium / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000737:chemistry* / Q000648:ultrastructure*; D012996:Solutions; D013055:Spectrophotometry, Infrared
D012996:Solutions; D004247:DNA; D004996:Ethidium