Figure 3. 3DNA-generated images of 22-bp DNA duplexes with the same overall 45° curvature per helical turn.

(a-d) four different theoretical distributions of roll angle achieving such curvature, according to models in the Calladine et al. textbook⁶⁰, namely two steps with 45° roll separated by a complete (10 bp) helical turn, five bends with 22.5° roll spaced at increments of a half helical turn and with alternating sign, two tracts of five 14°-rolled steps separated by a half helical turn, and a smoothly curved structure with a repeating sinusoidal-like variation in roll (−9.00°, −7.28°, −2.78°, 2.78°, 7.28°, 9.00°, 7.28°, 2.78°, −2.78°,−7.28°); (e) ideal B-DNA reference structure with uniform (zero) roll.