How does ethidium bromide interact with DNA?

Ethidium bromide (EtBr) intercalates with DNA. EtBr is a flat molecule with a ring structure that closely resembles the rings of the bases in DNA. This unique structure is what makes ethidium bromide a potent intercalating agent. The flat EtBr molecule easily inserts itself between the stacked bases in double-stranded DNA. This binding unwinds the double helix slightly, changing the conformation, weight, flexibility and charge of the DNA molecule. These distortions interfere with DNA transcription, replication, recombination and repair, causing different types of disorders in the cell function and cell cycle, which results in mutations.