Located at the Philipps-University-Marburg and the Max-Planck-Institute for terrestrial Microbiology in Marburg, Germany, the MarBAG employs X-ray crystallography to reveal fundamental mechanisms of key biological processes involving synthesis, assembly and function of macromolecular machines and cellular structures (e.g. CO2-fixation pathways, flagellar biosynthesis, CRISPR-Cas Systems, cell-wall-related processes, phage-bacteria relationships). Furthermore, we are interested in plant-pathogen interactions and the function of nucleotide derived signalling molecules in cellular stress physiology and organization. A 200 keV cryo-electron microscope was recently installed at the UMR to complement our efforts to structurally characterize macromolecular complexes, which do not readily crystallize. Thus, we can now routinely screen and quality check samples for cryo-electron microscopy and produce structures of 3Å resolution.