Which of the following is a common feature of DNA-binding motifs?

• A. Catalysis of peptide bond formation
• B. Incorporation of fatty acid chains for membrane attachment
• C. Direct involvement in ribosome assembly
• D. Presence of alpha-helices that fit into the major groove of DNA

Answer: (D)

Verified step by step guidance

1. Understand that DNA-binding motifs are specific structural features in proteins that allow them to interact with DNA molecules.
2. Recall that DNA has a double helix structure with major and minor grooves, which provide access points for protein binding.
3. Recognize that many DNA-binding motifs contain alpha-helices because these helices can fit snugly into the major groove of DNA, allowing specific interactions with base pairs.
4. Eliminate options that are unrelated to DNA binding, such as catalysis of peptide bond formation (which occurs in ribosomes), incorporation of fatty acid chains (related to membrane attachment), and direct involvement in ribosome assembly.
5. Conclude that the common feature of DNA-binding motifs is the presence of alpha-helices that fit into the major groove of DNA, facilitating specific and stable protein-DNA interactions.