on the DNA strand which grooves interact with protein major or minor grooves

Answer 1

Both the major and minor grooves on the DNA strand can interact with proteins.

The major groove is wider and deeper than the minor groove, allowing for more amino acid residues of the protein to make contact with the DNA bases. This makes the major groove a preferred site for protein-DNA interactions that require extensive contacts, such as sequence-specific DNA binding proteins.

On the other hand, the minor groove is narrower and shallower, limiting the number of amino acid residues that can interact with the DNA bases. However, the minor groove is still involved in protein-DNA interactions. Some proteins utilize the minor groove for indirect recognition of the DNA sequence, by reading the specific pattern of chemical groups on the bases.

In summary, both major and minor grooves on the DNA strand can interact with proteins, although the major groove is generally the preferred site for extensive protein-DNA interactions.