Extended Data Fig. 6: Cargo Complex Diffusion Constants.
From: Super-resolved 3D tracking of cargo transport through nuclear pore complexes
a, 3D step-size histogram for M9-βGal complexes. Step sizes of M9-βGal complexes were calculated from consecutive localizations in the trajectories of Fig. 4c (N = 824 total jump distances from 10 nuclei; each nucleus was an independent biological replicate). Data were fit using Eq. 4, yielding three distinct diffusion constants of 0.2 (18%), 0.8 (50%) and 2.6 (32%) µm2/s, or a weighted average diffusion constant of 1.3 µm2/s. b, 3D step-size histogram for NLS-2xBFP complexes. Step sizes of NLS-2xBFP complexes were calculated from consecutive localizations in the trajectories of Fig. 5c (N = 660 total jump distances from 10 nuclei; each nucleus was an independent biological replicate). Fitting the histogram yielded two distinct diffusion constants of 0.6 (25%) and 2.7 (75%) µm2/s, or a weighted average diffusion constant of 2.2 µm2/s. Due to the highly confined, irrregular volume sampled by the cargo complexes, these average diffusion constant estimates are considered both approximate and an underestimate. For comparison, the diffusion constant of the M9-βGal and NLS-2xBFP cargo complexes in aqueous buffer are approximated as ~34 and 55 µm2/s, respectively, using the Stokes-Einstein equation and a protein density of ~1.35 g/cm3 (ref. 83). Source numerical data are provided in source data.
