This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Structure and function of protein, Subject name: Biochemistry
[{'content': 'Proteins which have DNA binding domain in its structure are \nSelect and explain. \nA. Zinc finger, B. b - Sheet, C. b - band, D. Beta meander', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The specificity involved in the control of transcription requires that regulatory proteins bind with high affinity and specificity to the correct region of DNA. Three unique motifs--the helix-turn-helix, the zinc finger, and the leucine zipper-- account for many of these specific protein-DNA interactions.Harper 30th edition pg: 444', 'role': 'assistant'}]