• Sequence-Specific Protein-DNA Interactions:
• DNA-binding proteins (transcription factors, repressors, zinc fingers, helix-turn-helix, leucine zippers) recognize and bind specific DNA target motifs without melting the double helix.
• They achieve this by inserting $\alpha$-helical recognition motifs into the major and minor grooves of the B-DNA double helix, where the functional hydrogen-bond donors, acceptors, and methyl groups of individual base pairs are exposed in unique geometrical patterns.
• nalysis:
• (interacting with the bases in the major and minor grooves of the double helix): Correct.

Correct option: (4) interacting with the bases in the major and minor grooves of the double helix.