Which of the following secondary structures may be a DNA-binding domain?
A)Zinc finger
B)Leucine zipper
C)Helix-turn-helix
D)A and B only
E)A,B,and C

Question

Quizplus · Accepted Answer

All three of the listed secondary structures (zinc finger, leucine zipper, and helix-turn-helix) have been identified as DNA-binding domains. Zinc fingers contain a zinc ion coordinated by a group of conserved cysteine and histidine residues, which interact with specific DNA sequences. Leucine zippers are formed by a dimerization of two alpha-helices, each containing a repeating sequence of leucine residues, which can interact with DNA. Helix-turn-helix domains consist of two alpha-helices connected by a short turn, and one alpha-helix fits into the major groove of DNA, recognizing specific DNA sequences. Therefore, the best choice is E, since all three options are known DNA-binding domains.

Which of the Following Secondary Structures May Be a DNA-Binding