Question

A relaxed B-type double stranded circular DNA molecule of 8,400 base pairs was cleaved by an E. coli Type II topoisomerase. What was the original linking number (Lko) and the final linking number (Lk) for this DNA molecule?

a. Lko=1,200; Lk=1,199

b. Lko=800; Lk=802

c. Lko-400; Lk=401

d. Lko+800; Lk=798

e. Lko=400; Lk=399

An explanation of the answer would be appreciated, thanks!

The rate of bp/turn = 10.5.

Answer 1