What determines that the polar basic amino acids interact significantly with DNA?

The polar basic amino acids interact significantly with DNA primarily due to their positive charge. These amino acids, such as lysine and arginine, possess side chains that are positively charged at physiological pH. DNA, which has a negative charge due to its phosphate backbone, exhibits strong electrostatic attraction with these positively charged side chains. This interaction is crucial for the binding of proteins to DNA, facilitating processes such as transcription, replication, and repair.

The positive charge allows basic amino acids to stabilize their interaction with the negatively charged DNA, enabling effective binding and participation in various biochemical processes.