We report on quantitative single-molecule localization microscopy, a method that next to super-resolved images of cellular structures provides information on protein copy numbers in protein clusters. This approach is based on the analysis of blinking cycles of single fluorophores, and on a model-free description of the distribution of the number of blinking events. We describe the experimental and analytical procedures, present cellular data of plasma membrane proteins and discuss the applicability of this method.
The transport of water, protons, and nucleic acids through carbon nanotubes was studied with all-atom molecular dynamics simulations. Water is found to fill even narrow pores of sub-nanometer diameter, but the filling is sensitive to the strength of attractive pore-water interactions. Motions of the resulting water wires is fast on a molecular scale. Protons were also found to move rapidly along one-dimensionally ordered water chains with a hopping mechanism. The transport of nucleic acids through nanotube membranes is dominated by polymer conformational dynamics during entry, and hydrophobic attachment to the pore walls during exit.