Table 2.

Equilibrium forces (f), torques (τ), relative extensions (l/l₀), and twist for P-form nucleic acids calculated from umbrella sampling simulations at ρ = 1 (see text for details)

Structure	f pN	τ, pN·nm	l/l0	Twist, bp/turn
B-DNA	—	—	1.0	10.5
P-DNA	25.7 ± 9.7 (30)	34.8 ± 3.2 (34)	1.57 (1.6–1.75)	2.35 (2.4–2.6)
A-RNA	—	—	0.86	10.7
P-RNA	30.8 ± 12.8	40.5 ± 6.4	1.71	3.00

The numbers in parentheses are corresponding experimental data, where available, from refs. 14, 25, and 26.