title: Reversible toroidal compaction of DNA by aluminum.
abstract: Electron microscopy has been used to characterize the products of the reactions of aluminum with DNA under three different conditions, one of which, pH 5 and Al (III)/DNA(P) ratio of 0.4, has been previously shown to produce reversible interstrand crosslinking in double-stranded DNA molecules. Under this condition, aluminum produced macromolecular aggregates of DNA upon heating, with a distinctive ultrastructure reversible to double-stranded DNA after removal of the aluminum. These structures were toroidal in configuration and exhibited mean widths of 4.9 +/- 1.8 nm and were 18.6 +/- .4 nm in diameter with a toroidal internal diameter of 7.4 +/- 4.7 nm. Previous results have shown that these structures contain Al(III) - crosslinked DNA, the present data suggests that this intermolecular crosslinking is associated with the production of compacted structures.
authors.affiliation: Department of Diagnostic Radiology, University of Western Ontario, Canada.
authors.forename: S J
authors.initials: SJ
authors.lastname: Karlik
authors.forename: A A
authors.initials: AA
authors.lastname: Chong
authors.forename: G L
authors.initials: GL
authors.lastname: Eichhorn
authors.forename: U
authors.initials: U
authors.lastname: De Boni
mesh_terms: D000535:Aluminum / Q000494:pharmacology*; D003432:Cross-Linking Reagents; D004247:DNA / Q000187:drug effects* / Q000648:ultrastructure; D008854:Microscopy, Electron / Q000379:methods; D012996:Solutions
chemical_list: D003432:Cross-Linking Reagents; D012996:Solutions; D004247:DNA; D000535:Aluminum