title: Differential effects of spermine and its analogues on the structures of polynucleotides complexed with ethidium bromide.
abstract: The interactions of spermine and polyamine analogues with synthetic polynucleotides of various base sequences complexed with ethidium bromide (EB) were investigated using measurements of fluorescence intensity and steady-state fluorescence polarization. Spermine and polyamine analogues displaced some but not all of the EB bound to poly(dA-dT).poly(dA-dT) or poly(dG-dC).poly(dG-dC), suggesting that polyamines may stabilize these polynucleotides in a conformation with reduced affinity for EB. Modifications of the aliphatic backbone of spermine have pronounced effects on its ability to displace EB from poly(dA-dT).poly(dA-dT) but not from poly-(dG-dC).poly(dG-dC). Spermine and some but not all of the polyamine analogues caused fluorescence depolarization when they interacted with the complex of EB and poly(dA-dT).poly-(dA-dT). Neither spermine nor any of the analogues, however, induced fluorescence depolarization in the complex of EB with poly(dG-dC).poly(dG-dC) or poly(dA).poly(dT). This suggests that spermine and some spermine analogues induce structural changes specific to alternating A-T sequences.
authors: Department of Neurological Surgery, School of Medicine, University of California, San Francisco 94143.
authors: J G
authors: JG
authors: Delcros
authors: M C
authors: MC
authors: Sturkenboom
authors: H S
authors: HS
authors: Basu
authors: R H
authors: RH
authors: Shafer
authors: J
authors: J
authors: Szöllösi
authors: B G
authors: BG
authors: Feuerstein
authors: L J
authors: LJ
authors: Marton
mesh_terms: D004996:Ethidium / Q000737:chemistry*; D005454:Fluorescence Polarization; D009690:Nucleic Acid Conformation; D011067:Poly dA-dT / Q000737:chemistry; D011073:Polyamines / Q000494:pharmacology*; D011089:Polydeoxyribonucleotides / Q000737:chemistry; D011119:Polynucleotides / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013096:Spermine / Q000494:pharmacology*
chemical_list: D011073:Polyamines; D011089:Polydeoxyribonucleotides; D011119:Polynucleotides; D011067:Poly dA-dT; C019530:poly(dC-dG); D013096:Spermine; D004996:Ethidium