Structural studies on dinuclear ruthenium(II) complexes that bind diastereoselectively to an antiparallel folded human telomere sequence.

ABSTRACT: We report DNA binding studies of the dinuclear ruthenium ligand [{Ru(phen)2}2tpphz](4+) in enantiomerically pure forms. As expected from previous studies of related complexes, both isomers bind with similar affinity to B-DNA and have enhanced luminescence. However, when tested against the G-quadruplex from human telomeres (which we show to form an antiparallel basket structure with a diagonal loop across one end), the ΛΛ isomer binds approximately 40 times more tightly than the ΔΔ, with a stronger luminescence. NMR studies show that the complex binds at both ends of the quadruplex. Modeling studies, based on experimentally derived restraints obtained for the closely related [{Ru(bipy)2}2tpphz](4+), show that the ΛΛ isomer fits neatly under the diagonal loop, whereas the ΔΔ isomer is unable

SUBMITTER: Wilson T 

PROVIDER: S-EPMC3835060 | biostudies-literature | 2013 Nov

REPOSITORIES: biostudies-literature