Solid-to-fluid – like DNA transition in viruses facilitates infection

Journal Article · Tue Oct 14 04:00:00 EDT 2014 · Proceedings of the National Academy of Sciences of the United States of America

DOI:https://doi.org/10.1073/pnas.1321637111· OSTI ID:1241334

Liu, Ting; Sae-Ueng, Udom; Li, Dong; Lander, Gabriel C.; Zuo, Xiaobing; Jonsson, Bengt; Rau, Donald; Shefer, Ivetta; Evilevitch, Alex

Releasing the packaged viral DNA into the host cell is an essential process to initiate viral infection. In many double-stranded DNA bacterial viruses and herpesviruses, the tightly packaged genome is hexagonally ordered and stressed in the protein shell, called the capsid. DNA condensed in this state inside viral capsids has been shown to be trapped in a glassy state, with restricted molecular motion in vitro. This limited intracapsid DNA mobility is caused by the sliding friction between closely packaged DNA strands, as a result of the repulsive interactions between the negative charges on the DNA helices. It had been unclear how this rigid crystalline structure of the viral genome rapidly ejects from the capsid, reaching rates of 60,000 bp/s. Through a combination of single- molecule and bulk techniques, we determined how the structure and energy of the encapsidated DNA in phage λ regulates the mobility required for its ejection. Our data show that packaged λ -DNA undergoes a solid-to-fluid – like disordering transition as a function of temperature, resultin g locally in less densely packed DNA, reducing DNA – DNA repulsions. This p rocess leads to a sig- nificant increase in genome mobility or fluidity, which facilitates genome release at temperatures close to that of viral infection (37 °C), suggesting a remarkab le physical adaptation of bac- terial viruses to the environment of Escherichia coli cells in a human host.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: USDOE Office of Science - Office of Basic Energy Sciences; USDOE Office of Science - Office of Basic Energy Sciences - Scientific User Facilities Division; National Institutes of Health (NIH); Swedish Research Council; National Institutes of Health (NIH) - National Institute of Child Health and Human Development (NICHD); National Science Foundation (NSF)
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1241334
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America, Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Issue: 41 Vol. 111; ISSN 0027-8424
• Publisher: National Academy of Sciences, Washington, DC (United States)
• Country of Publication: United States
• Language: English

Related Subjects

AFM
DNA ejection
DNA fluidity
intracapsid DNA transition
isothermal titration calorimetry