Proteins in adenovirus (7th of May, 2015)

proteins, adenovirus

Viruses keep their DNA molecule within a protein coating, the capsid. The capsid volume is often small so that the DNA must be packed in it with the help of special mechanisms. Viruses have to that end evolved different strategies. Some pack with DNA highly basic cellular proteins which enable compaction of (negative) DNA, and some produce their own proteins for such purpose. >> Adenoviruses belong to this class. But, how the "condensing", "compacting" proteins are distributed within a virus, what is their relation to viral DNA, and how does the conformation of the DNA molecule look like is unknown. It is still a mystery, even after >> our paper :)

And our paper attempts to answer these questions by studying the cryo-electron tomograms which were analyzed so to extract the three-dimensional positions of "specks" which were identified with condensation proteins (adenosomes). My coworker and PhD student Sanjin Marion and I analyzed these positions to see whether there is some regularity in the distribution of "specks" and whether we can conclude something regarding their interaction.

>> We concluded that the protein distribution looks like a distribution of particles in a fluid - one observes quite soft repulsive interaction between the proteins and weak ordering of the first neighbors. Further neighbors effectively do not "feel" each other. Thus, the adenosomes behave like a fluid of soft balls. There is not even an indication that they are connected, which would be expected knowing that they bind the DNA molecule. The effective interactions in the densely packed interior of a virus are obviously quite different from those operating when the content of the virus is emptied in the free space - in that case one observes condensation proteins as "beads" connected together by the DNA molecule ("string").

Concerning SciVis, this time it came mainly from the experiment (above), from cryo-electron images (a) which were analyzed in order to get three-dimensional coordinated of the proteins / adenosomes (b) and a model of the virus (c).

Last updated on 7th of May 2015.