title: Recognition of DNA three-way junctions by metallosupramolecular cylinders: gel electrophoresis studies.
abstract: The interaction of metallosupramolecular cylinders with DNA three-way junctions has been studied by gel electrophoresis. A recent X-ray crystal structure of a palindromic oligonucleotide forming part of a complex with such a cylinder revealed binding at the heart of a three-way junction structure. The studies reported herein confirm that this is not solely an artefact of crystallisation and reveal that this is a potentially very powerful new mode of DNA recognition with wide scope. The cylinders are much more effective at stabilizing three-way junctions than simple magnesium di-cations or organic or metallo-organic tetra-cations, with the M cylinder enantiomer being more effective than P. The recognition is not restricted to three-way junctions formed from palindromic DNA with a central AT step at the junction; non-palindromic three-way junctions and those with GC steps are also stabilised. The cylinder is also revealed to stabilise other Y-shaped junctions, such as that formed at a fraying point in duplex DNA (for example, a replication fork), and other DNA three-way junction structures, such as those containing unpaired nucleotides, perhaps by opening up this structure to access the central cavity.
authors.affiliation: Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, 61265 Brno, Czech Republic.
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Malina
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hannon
authors.forename: Viktor
authors.initials: V
authors.lastname: Brabec
mesh_terms: D001483:Base Sequence; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods*; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
chemical_list: D008670:Metals; D004247:DNA