title: Hydrophobic vs coulombic interactions in the binding of steroidal polyamines to DNA.
abstract: Seven new steroidal polyamines derived from bile acids, either lithocholic or deoxycholic acid, have been studied as DNA-binding agents using four complimentary methods: an ethidium displacement assay, observed changes in the thermal denaturation of poly[d(AT)], effects on hyperchromicity of DNA, and circular dichroism. In addition, modelling studies were conducted to examine the electrostatic surface potential of the polycations. The results point to a key role for a large hydrophobic surface area on the steroid in addition to the Coulombic attraction by ammonium and guanidinium groups on the steroid interacting with the polyphosphate backbone.
authors.affiliation: Department of Chemistry, University of Utah, Salt Lake City 84103, USA.
authors.forename: J G
authors.initials: JG
authors.lastname: Muller
authors.forename: M M
authors.initials: MM
authors.lastname: Ng
authors.forename: C J
authors.initials: CJ
authors.lastname: Burrows
mesh_terms: D001647:Bile Acids and Salts / Q000737:chemistry; D002412:Cations; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004996:Ethidium / Q000737:chemistry / Q000378:metabolism; D019791:Guanidine; D006146:Guanidines / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009692:Nucleic Acid Heteroduplexes; D011073:Polyamines / Q000737:chemistry* / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D013329:Structure-Activity Relationship; D013696:Temperature
chemical_list: D001647:Bile Acids and Salts; D002412:Cations; D006146:Guanidines; D009692:Nucleic Acid Heteroduplexes; D011073:Polyamines; D000644:Quaternary Ammonium Compounds; D004247:DNA; D004996:Ethidium; D019791:Guanidine