Condensed DNA structure in bacteria subjected to various types of stress

Krupyanskii Y.F., Loiko N.G.1, Tereshkina K.B., Kovalenko V.V., .Tereshkin E.V., Sokolova O.S.2, Popov A.N.

Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences,, Moscow, 4 Kosygina ul., 119991, Russia

1Winogradsky Institute of Microbiology, Fundamentals of Biotechnology Federal Research Center

2Faculty of Biology, Lomonosov Moscow State University, 1 Leninskie gory, Moscow

3European Synchrotron Radiation Facility, Grenoble Cedex 9, France

Actively growing cells maintain a dynamic, out-of-equilibrium order through metabolism. Under starvation stress or under the influence of an analogue of the autoinducer of anabiosis (4-hexylresorcinol), cells go into a dormant state (almost complete absence of metabolism) or even into a mummified state (complete absence of metabolism). In a dormant state , cells are forced to use physical mechanisms to protect DNA. Using X-ray diffraction of synchrotron radiation and transmission electron microscopy (TEM), the architecture of DNA in the dormant and mummified state of cells was studied. Diffraction experiments indicate the appearance of an ordered organization of DNA. TEM made it possible to visualize the type of DNA ordering. Intracellular nanocrystalline, liquid crystalline, and folded nucleosome-like DNA structures have been discovered. The structure of DNA inside cells in the anabiotic dormant state and the dormant state (starvation stress) coincide (they form nanocrystalline structures). The data suggest the universality of DNA condensation with the Dps protein for the dormant state, regardless of the type of stress. The mummified state is very different in structure from the resting state (has no order within the cell).


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