Almost all bacteria owe their structure to an outer cell wall that interacts closely with the supporting MreB protein inside the cell. As scientists at the Max Planck Institute for Biochemistry and at the French INRA now show, MreB molecules assemble into larger units, but not - as previously believed – into continuous helical structures.
The circular movement of these units along the inside of the bacterial envelope is mediated by cell wall synthesis, which in turn requires the support of MreB. This mutual interaction may be a widespread phenomenon among bacteria and opens up new avenues for therapeutic intervention. The bacterial cell wall is already a major target for antibiotics. (Science, June 3, 2011)
Even single cells have to maintain their shape: In higher organisms, the supporting structures of the cytoskeleton, which include filament networks made of the protein actin, take care of this job. The much smaller bacterial cells possess similar cytoskeletal structures, such as the actin related protein MreB. Up to now, scientists believed that this molecule forms spiral structures on the inside of the cell membrane in non-spherical bacteria, which serve as a scaffold for the assembly of the comparatively rigid cell wall.
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