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DNA Packaging Mechanisms Revealed: From Entropy to Tension

Explore the intricate mechanisms of DNA virus assembly and packaging, delving into the interplay of entropy, bending elasticity, and tension in the DNA strand. Learn how molecular forces impact the process and discover the entropic costs associated with confinement. Uncover groundbreaking studies on DNA packaging costs and the role of motors in the packaging process. Investigate the thermodynamics of bacteriophage DNA packaging through calorimetry, revealing stored energy within packaged DNA. Stay informed about the latest research and advancements in understanding DNA packaging dynamics.

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DNA Packaging Mechanisms Revealed: From Entropy to Tension

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  1. Gaussian Chain • Entropy only. • Infinite extensibility. 2. Freely Jointed Chain. Entropy. Finite extensibility. Rigid rods.  3. Wormlike Chain. Entropy. Finite extensibility. Bending elasticity. Smooth curve like cooked spaghetti.

  2. Persistence length   = 50nm  = 6mm = bigger than a cell  = 17m

  3. Mechanism of DNA virus assembly and DNA packaging Rao and Feiss – Annu Rev Virol (2015) 2(1): 351–378 Costs of DNA packaging: DNA bending + Electrostatic repulsion of charged DNA + Entropic cost of confinement

  4. Measuring the force generated by T4 DNA packaging motors Fuller et al PNAS (2007) 104: 16868-16873 Tension in the DNA increases as packaging proceeds. Eventually the tether breaks. Speed of motpor decreases as tension increases.

  5. Differential Scanning Calorimetry of Bacteriophage . Exothermic peaks associated with Capsid denaturation and DNA melting. Endothermic peak due to DNA ejection. Shows that there was significant stored energy in the packaged DNA Bauer et al J Virol (2015) 89:9288-9298

  6. Kunze and Netz (2000)

  7. Brower-Toland et al 2002

  8. Mihardja et al (2006)

  9. Kulic and Schiessel 2004

  10. Tomschik et al 2005

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