Table 2. Measured value of the contour length and measured persistence length from end-to-end distance measurements, fit to models for two-dimensional WLC, three-dimensional WLC, and projection of 3D WLC onto a 2D surface, as described by eqn (3), (4), and (5). Uncertainty in measured length is standard error for at least 13 measurements. Uncertainty in persistence length is propagated from uncertainty in end-to-end distance (Fig. 1d) and contour length measurements.

Construct	DNA length (bp)	DNA measured length (bp)	2D persistence length using end-to-end distance (nm)	3D persistence length using end-to-end distance (nm)	Persistence length from projection of 3D on 2D (nm)
pUC18	1650	1624 ± 96	26 ± 2.5	51.7 ± 5.1	77.5 ± 7.6
mtDNA	1663	1684 ± 21	24.5 ± 2	48.9 ± 3.6	73.4 ± 5.4
pBR322 (air)13	4361	4353 ± 324	57 ± 6
pBR322 (liquid)	4361	4334 ± 116	25 ± 1	49.9 ± 2.4	74.9 ± 3.6