Which of the following is correct if the process includes a further treatment with a type IB topoisomerase that is active at a high salt solution? A plasmid with 4000 BP of closed circular duplex DNA was isolated from E. coli. It has a 300-BP segment of alternating C and G residues. Upon transfer to a high salt solution, this segment undergoes a transition from the B conformation to the Z conformation. Given that B-DNA contains one right-handed turn per 10 base pairs, Z-DNA contains one left-handed turn per 12 base pairs and linking number (L) equals twist (T) plus the writhing number (W).
A. Its linking number is not changed B. The change in its writhing number is 55 C. Its original linking number is 400 D. The change in its twist is -55 E. All answers are correct