4. The transition of B-DNA to Z-DNA can be induced in negatively supercoiled covalently closed circular DNA molecules. Consider the transition of B-DNA to Z-DNA confined to a 12 base pair alternating d(CG) sequence in a covalently closed circular DNA molecule. Calculate the conformational change due to this transition and explain what this conformational change means. Use 10.5 base pairs/turn for B-DNA. Ignore B-to-Z junctions.