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Architecture of Condensed DNA in the Nucleoid of Escherichia coli Bacteriumстатья
- Авторы: Krupyanskii Y.F., Kovalenko V.V., Loiko N.G., Generalova A.A., Moiseenko A.V., Tereshkin E.V., Sokolova O.S., Tereshkina K.B., El’-Registan G.I., Popov A.N.
- Журнал: Biophysics
- Том: 67
- Номер: 4
- Год издания: 2022
- Издательство: Maik Nauka/Interperiodica Publishing
- Местоположение издательства: Russian Federation
- Первая страница: 506
- Последняя страница: 517
- DOI: 10.1134/s0006350922040133
- Аннотация: The three-dimensional (3D) architecture of the genome determines cell function. The study of DNA condensation in the cell is important for understanding the mechanisms of bacterial survival and for medicine, since ordered DNA condensation provides antibiotic resistance to pathogenic bacteria . In a dilute solution, the length of DNA is several centimeters. The length of an Escherichia coli bacterium is approximately 2.0 μm. Such a dramatic decrease in the volume occupied by DNA is a consequence of its condensation. It was found that DNA is hierarchically organized in the nucleoid with three levels of DNA compaction: the lowest level (small scale ≥1 kb bp) is provided by histone-like NAP proteins. Unlike actively growing bacteria, bacteria under starvation stress use an energy-independent mechanism to maintain the order and protect vital structures (DNA), as in inanimate nature. The study of the DNA structure in the nucleoid of E. coli bacterium was carried out using synchrotron X-ray diffraction and transmission electron microscopy. The experimental results allowed visualization of the structures of the lowest hierarchical level of DNA compaction in the nucleoid of dormant cells. The series of diffraction experiments performed for the first time indicates the presence of a periodic ordered organization of DNA in all studied bacteria. The transmission electron microscopy provided more subtle visual information about the type of DNA condensation in the nucleoid of E. coli bacterium. Intracellular nanocrystalline, liquid-crystalline, and folded nucleosome-like structures of DNA were found. A folded nucleosome-like structure was observed for the first time, it is a result of multiple folding of long DNA molecules around Dps protein and its associates.
- Добавил в систему: Терешкина Ксения Борисовна