Oral Presentation 2014 International Biophysics Congress

Solid-to-fluid DNA transition in viruses facilitates infection     (#216)

Alex Evilevitch 1 , Ting Liu 1 , Udom Sae-Ueng 1 , Li Dong 1 , Gabriel Lander 2 , Xiaobing Zuo 3 , Bengt Jonsson 4 , Donald Rau 5 , Ivetta Shefer 1
  1. Carnegie Mellon University, Pittsburgh, PA, USA
  2. Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
  3. Advanced Photon Source, Argonne National Laboratory, Argonne, IL, USA
  4. Department of Biophysical Chemistry, Lund University, Lund, Sweden
  5. Laboratory of Physical and Structural Biology, National Institutes of Health, Bethesda, MD, USA

Physical virology presents a new direction that aims to provide a physical description of common mechanisms controlling viral replication for a broad range of viruses. Releasing the packaged viral DNA into the host cell is an essential process to initiate viral infection. In many double-stranded DNA bacterial viruses (phage) and herpesviruses, the tightly packaged genome is hexagonally ordered and stressed in the protein shell called the capsid. DNA condensed in this state has been shown to have restricted fluidity. It has remained unclear how this rigid crystalline structure of the viral genome rapidly ejects from the capsid, reaching rates of 60,000 base pairs per second. Through a combination of single-molecule and bulk techniques, we determined how the structure and energy of the encapsidated DNA in phage lambda regulates its fluidity required for ejection. Our data show that packaged lambda-DNA undergoes a solid-to-fluid disordering transition as a function of temperature, which facilitates rapid genome release at temperatures close to that of viral infection (37°C). This suggests a remarkable physical adaptation of bacterial viruses to the environment of E. coli cells in a human host.

  1. D. Bauer, F. Homa, J. Huffman, A. Evilevitch “HSV-1 genome, the pressure is on” JACS, 135 (30): 11216-11221, 2013.
  2. G. C. Lander, J. E. Johnson, D. C. Rau, C. S. Potter, B. Carragher, A. Evilevitch, “DNA bending induced phase transition of encapsidated genome in phage lambda”, Nucleic Acids Res. Apr 1:41(8):4518-4524, 2013.
  3. I. Ivanovska, B. Jönsson, G. Wuite, A. Evilevitch “Internal DNA pressure modifies stability of wild-type phage”, Proceedings of the National Academy of Sciences of the United States of America (PNAS), 104(23):9603-8, 2007.