DNA-binding domains are specific regions within proteins that interact directly with DNA. These domains enable proteins to recognize and bind to particular sequences of DNA, playing a crucial role in processes such as gene regulation, DNA replication, and DNA repair. Different types of DNA-binding domains exist, including zinc fingers, helix-turn-helix, and leucine zippers. Each type has a unique structure that allows it to attach to DNA in a specific manner, influencing how genes are expressed and how genetic information is maintained within cells.