title: DNA aggregation induced by polyamines and cobalthexamine.
abstract: We have studied the precipitation of short DNA molecules by the polycations spermidine, spermine, and cobalthexamine. The addition of these cations to a DNA solution leads first to the precipitation of the DNA; further addition resolubilizes the DNA pellet. The multivalent salt concentration required for resolubilization is essentially independent of the DNA concentration (between 1 microM/ml and 1 mg/ml) and of the monovalent cation concentration present in the DNA solution (up to 100 mM). The DNA aggregates are anisotropic; those obtained in the presence of the polyamines spermidine and spermine generally contain a cholesteric liquid crystalline phase that flows spontaneously. In contrast this phase is never seen in the presence of cobalthexamine. We propose that the ability of polyamines to condense DNA in fluid structures is an essential feature of their biological functions.
authors.affiliation: Laboratoire de Physique des Solides, Université Paris Sud, 91405 Orsay Cedex, France.
authors.forename: J
authors.initials: J
authors.lastname: Pelta
authors.forename: F
authors.initials: F
authors.lastname: Livolant
authors.forename: J L
authors.initials: JL
authors.lastname: Sikorav
mesh_terms: D000818:Animals; D001482:Base Composition; D002417:Cattle; D003035:Cobalt / Q000494:pharmacology*; D004247:DNA / Q000737:chemistry* / Q000187:drug effects*; D007700:Kinetics; D009994:Osmolar Concentration; D012965:Sodium Chloride / Q000494:pharmacology; D012995:Solubility; D012996:Solutions; D013095:Spermidine / Q000494:pharmacology*; D013096:Spermine / Q000494:pharmacology*; D013950:Thymus Gland
chemical_list: D012996:Solutions; C030862:cobalt ammonium complex; D013096:Spermine; D003035:Cobalt; D012965:Sodium Chloride; D004247:DNA; D013095:Spermidine