Ejecting phage DNA (31st of October 2014)

cross-sections of condensed DNA tori

In a paper recently published, >> Ejecting Phage DNA against Cellular Turgor Pressure Sanjin Marion, a PhD candidate who works on his PhD thesis with me, and I investigated mechanics and thermodynamics of DNA ejection from viruses (bacteriophages) to bacteria.

Although it was previously considered that the main physical mechanism for DNA ejection is a high pressures produced by a densely packed bacteriophage DNA, so that it is essentially injected in the bacteria, we have shown that the dominant mechanics could be a condensation of DNA molecule in a bacteria. The condensed DNA is observed typically tightly wounded in a torus, and the profiles of such tori are shown in the image above, for different types of bacteriophages.

Whether this is the only physical effect important for the explanation of the phenomenon, we cannot say with certainty, but we can say that it explains the translocation of DNA in spite of the turgor pressure within bacteria.

The paper was published in Biophysical Journal and one can >> download it HERE.

Last updated on 31st of October, 2014.