title: DNA-binding properties of amidine-substituted spiropyran photoswitches.
abstract: Two amidine-substituted spiropyran derivatives have been characterized with respect to the DNA-binding properties over a broad pH interval. The two derivatives differ in the number of positive charges. By varying the pH, the protonation state of the derivatives is also changed, allowing for additional variations in the charge distribution. We show that the closed spiro isomer does not bind for either of the two derivatives, whereas the open merocyanine forms bind both in the protonated and in the nonprotonated state, but with dramatically different binding constants. Flow-oriented linear dichroism (LD) measurements also show that there are differences in the binding modes between the various forms. We rationalize these differences in terms of structure and charge distribution.
authors.affiliation: Department of Chemical and Biological Engineering, Physical Chemistry, Chalmers University of Technology, 412 96 Göteborg (Sweden).
authors.forename: Martin
authors.initials: M
authors.lastname: Hammarson
authors.forename: Jesper R
authors.initials: JR
authors.lastname: Nilsson
authors.forename: Shiming
authors.initials: S
authors.lastname: Li
authors.forename: Per
authors.initials: P
authors.lastname: Lincoln
authors.forename: Joakim
authors.initials: J
authors.lastname: Andréasson
mesh_terms: D000578:Amidines / Q000737:chemistry*; D001578:Benzopyrans / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D007536:Isomerism; D015394:Molecular Structure; D009574:Nitro Compounds / Q000737:chemistry*
chemical_list: D000578:Amidines; D001578:Benzopyrans; D007211:Indoles; D009574:Nitro Compounds; C548873:merocyanine; C088184:spiropyran; D004247:DNA
keywords: DNA; DNA-binding; photochromism; photoswitches; spiropyrans