Biophysical analysis demonstrates AT-dependent, non-intercalating DAPI binding to nucleic acids, suggesting an interaction model resembling netropsin and distamycin.
Key Points
To characterize the binding mechanisms, sequence dependence, and structural interactions between diamidino-2-phenylindole (DAPI) and natural or synthetic nucleic acids.
Evaluated DAPI interactions across natural and synthetic polydeoxynucleotides differing in base content and sequence.
Conducted circular dichroism, analytical ultracentrifugation, viscometry, and calorimetry to examine binding energetics and hydrodynamic properties.
Identified two distinct binding modes across all tested polymers, with interaction strength and stability against ionic strength directly correlating with adenine-thymine (AT) cluster content.
Sedimentation velocity measurements ruled out an intercalation mechanism, supporting an external binding model structurally similar to netropsin and distamycin.