Calculate values for the following topological properties of a closed-circular DNA molecule containing 2000 base pairs (for simplicity, assume there are 10 base pairs per turn in the relaxed DNA). (a) The linking number when the DNA is relaxed
(b) The linking number when the DNA has been underwound by 10 enzymatic turnovers of DNA gyrase (+ATP)
(c) The linking number when the DNA has been underwound by binding five nucleosomes followed by complete relaxation by a eukaryotic topoisomerase
(d) The superhelical density of the DNA molecule in (b)
(e) The superhelical density of the DNA molecule in (c)