Integrative structural analysis of multi-stress resistant organisms
Harald Bernhard, Lorenzo Gaifas, Eymeline Pageot, Ambroise Desfosses, Maria Bacia, Irina Gutsche
In parallel to investigating fractionated cell extracts of a multi-stress resistant organism by high-throughput single particle cryo-EM, as presented above, we seek to contextualise the obtained in vitro structural information by analysing the same organism using in situ cryo-ET, and to investigate structure-function relationships of selected complexes in more detail by classical cryo-EM combined with other imaging, biochemical and modelling approaches. One of our current model systems is Deinococcus radiodurans, chosen for its relatively large size, unusual morphology, non pathogenicity and extraordinary resistance to X-ray and UV radiation. An additional motivation for the choice of this specific bacterium is the possibility to closely collaborate with Joanna Timmins, an expert in D. radiodurans genome organisation and repair in response to irradiation. We recently set out to study D. radiodurans cell division, the associated cell wall synthesis and rearrangements, and the concurrent chromosome multiplication and segregation into the daughter cells using single particle cryo-EM, cryo-FIB/SEM, cryo-ET and cryo-soft X-ray tomography. At present, we concentrate more specifically on the DNA-binding and bending protein HU, the cell division protein FtsZ and the ribosome. However, the cryo-EM micrographs of cell extracts and the lamella tomograms contain a wealth of information that we may explore in future studies.
Collaborations :
– Joanna Timmins and Jean-Philippe Kleman, I2SR, IBS
– Linda Sandblad and UCEM, Umeå University, Sweden