THE ROLE OF LIQUID CRYSTAL ORDERING IN THE STRUCTURAL ORGANIZATION OF DNA IN BACTERIA.
This paper presents and critically reviews the results of original and some literature based experimental studies conducted by the authors last years on the structural organization of DNA in dormant (starvation stress), anabiotic dormant (4 HR treatment) E. coli cells, as well as the K12 {Delta}dps strain, which lacks the Dps protein (Dps null E. coli). The experimental data includes small-angle…
A recent paper delves into the intricate structural organization of DNA within dormant and anabiotic dormant E. coli cells, including the K12 Δdps strain, which lacks the Dps protein. Researchers employed small-angle synchrotron radiation diffraction (SAXS) and transmission electron microscopy (TEM) experiments to gather data. Analysis revealed that peaks at 44.3, 22.1, and 14.8 angstrom resolutions are exclusively linked to ordered DNA organization in both K12Δdps cells and dormant/anabiotically dormant cells. Thus, this ordered DNA arrangement also manifests in dormant and anabiotically dormant cells.
The authors propose a cholesteric liquid crystal model to explain the ordered DNA organization in the cell. Computational models based on this hypothesis align well with experimental SAXS data from Dps-null cell samples. Consequently, the cholesteric liquid crystal model emerges as a fitting representation of DNA packaging in dormant and anabiotically dormant cells.
Researchers contend that cholesteric liquid crystal ordering should be considered in future models of cellular DNA organization. The paper also raises the intriguing question of whether the cholesteric liquid crystal or nanocrystalline structure predominates within the cell, or if both coexist and exhibit distinct characteristics depending on external conditions. Further advancements in structural analysis methods are necessary to resolve this issue.
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