Pycnometric, viscometric and calorimetric studies of the process to release the double-stranded DNA from the Un bacteriophage

Mdzinarashvili, T. J.; Mrevlishvili, G. M.; Khvedelidze, Mariam; Ivanova, A.; Janelidze, Nino; Kiziria, E. L.; Tushishvili, D.; Тедиашвили, Марина; Кемп, Р. Б.

doi:10.1016/j.bpc.2006.05.005

Cited by 6 publications

(7 citation statements)

References 17 publications

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“…[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] In particular, differential scanning calorimetry has been used in studies on virus stability, assembly, and maturation transition of viral capsids. [36][37][38][42][43][44] This work describes direct measurements of the change in enthalpy associated with DNA ejection from phage λ.…”

Section: Introductionmentioning

confidence: 99%

“…Calorimetric techniques have been successfully used in recent decades to measure energetic contributions in various studies involving proteins and nucleic acids [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] . In particular, differential scanning calorimetry (DSC) has been used in studies on virus stability, assembly and maturation transitions of viral capsids [36][37][38][42][43][44] . This paper describes direct measurements of the change in enthalpy associated with DNA ejection from phage !.…”

Section: Introductionmentioning

confidence: 99%

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DNA Heats Up: Energetics of Genome Ejection from Phage Revealed by Isothermal Titration Calorimetry

Jeembaeva

Jönsson

Castelnovo

et al. 2010

Journal of Molecular Biology

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Most bacteriophages are known to inject their double-stranded DNA into bacteria upon receptor binding in an essentially spontaneous way. This downhill thermodynamic process from the intact virion to the empty viral capsid plus released DNA is made possible by the energy stored during active packaging of the genome into the capsid. Only indirect measurements of this energy have been available until now, using either single-molecule or osmotic suppression techniques. In this work, we describe for the first time the use of isothermal titration calorimetry to directly measure the heat released (or, equivalently, the enthalpy) during DNA ejection from phage lambda, triggered in solution by a solubilized receptor. Quantitative analyses of the results lead to the identification of thermodynamic determinants associated with DNA ejection. The values obtained were found to be consistent with those previously predicted by analytical models and numerical simulations. Moreover, the results confirm the role of DNA hydration in the energetics of genome confinement in viral capsids.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

DNA Heats Up: Energetics of Genome Ejection from Phage Revealed by Isothermal Titration Calorimetry

Jeembaeva

Jönsson

Castelnovo

et al. 2010

Journal of Molecular Biology

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“…The above isothermal experiment, when actually performed in a laboratory, is exothermic [58]. Earlier experiments using differential scanning calorimetry led to the same conclusion [59][60][61]; i.e., the system releases an amount of heat, of magnitude Q ejection to the environment. This tells us that S ejection < 0; however, the amount of heat released to the environment cannot give us the value S ejection because the ejection process is spontaneous and irreversible.…”

Section: Entropy Of Dna Ejection In Vitromentioning

confidence: 73%

Dynamics of Bacteriophage Genome Ejection In Vitro and In Vivo

Panja,

Molineux

2010

Preprint

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Bacteriophages, phages for short, are viruses of bacteria. The majority of phages contain a double-stranded DNA genome packaged in a capsid at a density of ∼ 500 mg/ml. This high density requires substantial compression of the normal B form helix, leading to the conjecture that DNA in mature phage virions is under significant pressure, and that pressure is used to eject the DNA during infection. A large number of theoretical, computer simulation and in vitro experimental studies surrounding this conjecture has revealed many -though often isolated and/or contradictory -aspects of packaged DNA. This prompts us to present a unified view of the statistical physics and thermodynamics of DNA packaged in phage capsids. We argue that the DNA in a mature phage is in a (meta)stable state, wherein electrostatic self-repulsion is balanced by curvature stress due to confinement in the capsid. We show that in addition to the osmotic pressure associated with the packaged DNA and its counterions, there are four different pressures within the capsid: pressure on the DNA, hydrostatic pressure, the pressure experienced by the capsid, and the pressure associated with the chemical potential of DNA ejection. Significantly, we analyze the mechanism of force transmission in the packaged DNA, and demonstrate that the pressure on DNA is not important for ejection. We derive equations showing a strong hydrostatic pressure difference across the capsid shell. We propose that when a phage is triggered to eject by interaction with its receptor in vitro, the (thermodynamic) incentive of water molecules to enter the phage capsid flushes the DNA out of the capsid. In vivo, the difference between the osmotic pressures in the bacterial cell cytoplasm and the culture medium similarly results in a water flow that drags the DNA out of the capsid and into the bacterial cell.

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“…1). It should be noted that adding the membrane receptor FhuA to T5 phage suspension leads to a DNA ejection from a phage particle, and this process starts immediately after adding the receptor [15,17,21]. From a biologic point of view, it remains unclear why bacteriophages are absorbed on bacterial cell receptors as seen in the electron micrograph, and do not inject their DNAs into the cell cytoplasm (see Fig.…”

Section: The Impact Of Phages On Bacterial Cellsmentioning

confidence: 96%

“…To find the answer to this question, the experimental investigation of phage-bacteria interaction is to be carried out. Bacteriophages can help to solve this problem by means of simply counting the number of phages attached to the bacterial membrane; this can be done by employing an electron microscope [15,21]. We can determine the number of existing receptor sites on the bacterial surface by using image-producing techniques like electron microscopy (for example, Fig.…”

Section: Introductionmentioning

confidence: 99%

Features of Membrane Receptors in Bacterial Multiplication Process and Necessary Conditions for Phage Infection of Bacteria

et al. 2014

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According to the obtained experimental results, the thermal shock (from 37 to 53 °C) not only stops the multiplication process of Escherichia coli bacteria, but also causes bacterial titer to decrease gradually. After this period lasting up to 1 hour, the bacterial cells continue to grow. A similar type of response was observed when bacteria were subjected to acid shock. Increasing acidity of media leads to decrease of bacterial growth process, and finally, their titer curve sharply falls over time. Also, interesting results were obtained about necessary conditions for infecting the bacteria by phages. Particularly, DNA injection from phages into bacterial cells requires most of corresponding bacterial membrane receptors to be occupied by phages. We suppose that this occurs due to autocrine phenomenon when the signaling molecules block the DNA ejection from phage particles. This effect lasts until a certain number of phage particles are attached to the membrane. After that, DNA injection from phage head into the cytoplasm takes place and the process of bacterial infection begins. The real number of phages in a stock is by several orders higher than the number of plaque-forming units in a given stock, which is determined by a classical double-layer agar method.

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Pycnometric, viscometric and calorimetric studies of the process to release the double-stranded DNA from the Un bacteriophage

Cited by 6 publications

References 17 publications

DNA Heats Up: Energetics of Genome Ejection from Phage Revealed by Isothermal Titration Calorimetry

DNA Heats Up: Energetics of Genome Ejection from Phage Revealed by Isothermal Titration Calorimetry

Dynamics of Bacteriophage Genome Ejection In Vitro and In Vivo

Features of Membrane Receptors in Bacterial Multiplication Process and Necessary Conditions for Phage Infection of Bacteria

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