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Arghittu, S. M.

Publications and source records attributed to Arghittu, S. M..

2 recordsLinked to original sources

P116 from Mycoplasma is a self-sufficient lipid uptake and delivery machinery

Lipid acquisition and transport are fundamental processes in all organisms. Here, we investigate the lipid uptake and delivery mechanism of the minimal model organism Mycoplasma pneumoniae. We show that the essential protein P116 can transport lipids between liposomes independently and without ATP consumption. Our structural data and molecular dynamics simulations reveal the mechanism by which the N-terminal region of P116 perturbs the membrane, the lipid transfer route, and the regulation of membrane binding by the cargo mass within P116s large hydrophobic cavity. When adequately filled with cargo, P116 undergoes a rapid conformational change that modulates membrane binding. Taken together, our results show that Mycoplasma developed one integrated lipid uptake and delivery machinery that simplifies the complex multi-protein pathways used by higher developed organisms.

molecular biology↗

ArtiaX: An Electron Tomography Toolbox for the Interactive Handling of Sub-Tomograms in UCSF ChimeraX

Cryo-electron tomography analysis involves the selection of macromolecular complexes to be used for subsequent sub-tomogram averaging and structure determination. Here, we describe a plugin developed for UCSF ChimeraX that allows for the display, selection, and editing of particles within tomograms. Positions and orientations of selected particles can be manually set, modified and inspected in real-time, both on screen and in virtual reality, and exported to various file formats. The plugin allows for the parallel visualization of particles stored in several meta data lists, in the context of any 3D image that can be opened with UCSF ChimeraX. The particles are rendered in user-defined colors or using colormaps, such that individual classes or groups of particles, cross-correlation coefficients or other types of information can be highlighted to the user. The implemented functions are fast, reliable and intuitive, exploring the broad range of features in UCSF ChimeraX. They allow for a fluent human-machine interaction, which enables an effective understanding of the sub-tomogram processing pipeline, even for non-specialist users.

biophysics↗