Different interactions of spermine with a "curved" and a "normal" DNA duplex: (CA4T4G)n and (CT4A4G)n. Gel electrophoresis and circular dichroism studies.
Two nucleotide sequences, (CA4T4G)n and (CT4A4G)n, are generally considered as prototypes of a "curved" and a "normal" DNA duplex on the basis of their different behaviour with respect to physico-chemical and/or biochemical properties. We have studied their gel electrophoretic mobilities in the presence of the biologically significant tetracation spermine and have found that spermine causes a decrease of the gel electrophoretic mobility of "curved" DNA, but does not influence that of "normal" DNA. Circular dichroism spectra of the complexes between spermine and the two examined DNAs show dramatically different features. These findings suggest that different DNA superstructures are relevant in interactions not only with proteins, but also with polycations, such as spermine.
Bordin
F
F
Dipartimento di Genetica e Biologia Molecolare, Università di Roma La Sapienza, Italia.
Cacchione
S
S
Savino
M
M
Tufillaro
A
A
D001483:Base Sequence; D002412:Cations; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry; D012016:Reference Values; D013096:Spermine / Q000737:chemistry*
D002412:Cations; D009841:Oligonucleotides; D013096:Spermine; D004247:DNA