Michael A. Lomholt

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Fluorescence loss in photobleaching (FLIP) is a widely used imaging technique, which provides information about protein dynamics in various cellular regions. In FLIP, a small cellular region is repeatedly illuminated by an intense laser pulse, while images are taken with reduced laser power with a time lag between the bleaches. Despite its popularity, tools(More)
We study a Michaelis-Menten reaction for a single two-state enzyme molecule, whose transition rates between the two conformations are modulated by an harmonically oscillating external force. In particular, we obtain a range of optimal driving frequencies for changing the conformation of the enzyme, thereby controlling the enzymatic activity (i.e., product(More)
PACS 05.40.-a – Fluctuation phenomena, random processes, noise, and Brownian motion PACS 87.10.-e – General theory and mathematical aspects PACS 87.16.-b – Subcellular structure and processes PACS 87.18.-h – Biological complexity Abstract –Macromolecular crowding in living biological cells effects subdiffusion of larger bio-molecules such as proteins and(More)
We investigate the translocation of a stiff polymer consisting of M monomers through a nanopore in a membrane, in the presence of binding particles (chaperones) that bind onto the polymer, and partially prevent backsliding of the polymer through the pore. The process is characterized by the rates: k for the polymer to make a diffusive jump through the pore,(More)
UNLABELLED BACKGROUND Cholesterol is an important membrane component, but our knowledge about its transport in cells is sparse. Previous imaging studies using dehydroergosterol (DHE), an intrinsically fluorescent sterol from yeast, have established that vesicular and non-vesicular transport modes contribute to sterol trafficking from the plasma membrane.(More)
Recent experiments show that transcription factors (TFs) indeed use the facilitated diffusion mechanism to locate their target sequences on DNA in living bacteria cells: TFs alternate between sliding motion along DNA and relocation events through the cytoplasm. From simulations and theoretical analysis we study the TF-sliding motion for a large section of(More)
The fluctuation spectrum of a quasispherical vesicle with active membrane proteins is calculated. The activity of the proteins is modeled as the proteins pushing on their surroundings giving rise to nonlocal force distributions. Both the contributions from the thermal fluctuations of the active protein densities and the temporal noise in the individual(More)
The Acknowledgements section in this Article is incomplete. " RM acknowledges the Academy of Finland for support within the FiDiPro scheme. " should read: " RM acknowledges the Academy of Finland for support within the FiDiPro scheme. We acknowledge financial support of the Deutsche Forschungsgemeinschaft (DFG) and the Open Access Publication Fund of the(More)
We study the impact of DNA coiling on the search rate of proteins moving along the DNA contour interspersed by three-dimensional (3D) bulk excursions. When the DNA is coiled proteins performing short 3D hops along a DNA segment can be captured by foreign DNA segments that have looped back close to the original segment. These intersegmental jumps are shown(More)
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