Schönherr, Holger
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Publication Access status: Metadata only , Fluorimetric Cell Analysis with 9‐Aryl‐Substituted Berberine Derivatives as DNA‐Targeting Fluorescent ProbesDNA‐sensitive fluorescent light‐up probes based on berberine are presented. This biogenic fluorophore was chosen as central unit to use its potential biocompatibility and its DNA‐binding properties. To provide predictable fluorescence quenching in aqueous solution and a fluorescence light‐up effect upon DNA binding, aryl substituents were attached at the 9‐position by Suzuki‐Miyaura coupling reactions. The 9‐arylberberine derivatives have a very low fluorescence quantum yield ( Φ fl =<0.02), which is caused by the radiationless deactivation of the excited state by torsional relaxation about the biaryl axis. In addition, these berberine derivatives intercalate into DNA with high affinity ( K b =2.0−22×10 4 M −1 ). Except for the nitrophenyl‐ and hydroxyphenyl‐substituted derivatives, all tested compounds exhibited a pronounced fluorescence light‐up effect upon association with DNA, because the deactivation of the excited‐state by torsional relaxation is suppressed in the DNA binding site. Most notably, it was shown exemplarily with the 9‐(4‐methoxyphenyl)‐ and the 9‐(6‐methoxynaphthyl)‐substituted derivatives that these properties are suited for fluorimetric cell analysis. In particular, these probes generated distinct staining patterns in eukaryotic cells (NIH 3T3 mouse fibroblasts), which enabled the identification of nuclear substructures, most likely heterochromatin or nucleoli, respectively.Source Type:Article2 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Spectroscopic Investigation of the Quadruplex DNA‐Binding Properties of 9‐Aryl‐Substituted Isoquinolinium DerivativesThe spectroscopic investigation of the binding properties of berberine‐type 9‐aryl‐substituted isoquinolinium derivatives with G‐quadruplex DNA (G4‐DNA) are presented. Photometric titrations show that these ligands bind with high affinity to the telomeric G4‐DNA form 22AG ( K =1.0–44×10 5 M −2 ). Furthermore, fluorimetric analysis of thermal DNA denaturation (FRET melting) reveals a significant thermal stabilization of G4‐DNA 22AG upon association with the methoxy‐substituted derivatives. As an analytically useful property, the derivatives with a phenyl substituent or with additional electron‐donating groups show a very weak fluorescence intensity, which increased significantly upon G4‐DNA complexation (fluorescence light‐up effect). Additional time‐resolved fluorescence spectroscopy indicated increased fluorescence lifetimes of the DNA‐bound 9‐(4‐methoxyphenyl)‐substituted derivative, when interacting with the quadruplex‐forming strand 22AG . Notably, the changes of the steady‐state and time‐resolved emission properties of the ligand are more pronounced with G4‐DNA than with duplex DNA so that the combination of these complementary methods may be used for the selective G4‐DNA detection.Source Type:Article2
