DNA-binding protein

Cro protein complex with DNA

Interaction of DNA (orange) with histones (blue). These proteins' basic amino acids bind to the acidic phosphate groups on DNA.

The lambda repressor helix-turn-helix transcription factor bound to its DNA target

The restriction enzyme EcoRV (green) in a complex with its substrate DNA

DNA-binding proteins are proteins that have DNA-binding domains and thus have a specific or general affinity for single- or double-stranded DNA. Sequence-specific DNA-binding proteins generally interact with the major groove of B-DNA, because it exposes more functional groups that identify a base pair.