made with VMD
Viruses, the cause of many diseases, are the smallest natural organisms known. They are extremely primitive and parasitic such that biologists refer to them as "particles", rather than organisms. Viruses contain in a protein shell, the capsid, their own building plan, the genome, in the form of DNA or RNA. Viruses hijack a biological cell and make it produce from one virus many new ones. Viruses have evolved elaborate mechanisms to infect host cells, to to produce and assemble their own components, and to leave the host cell when it bursts from viral overcrowding. Because of their simplicity and small size, computational biologists selected a virus for their first attempt to reverse-engineer in a computer program, NAMD, an entire life form, choosing one of the tiniest viruses for this purpose, the satellite tobacco mosaic virus. As described in a recent report, the researchers simulated the virus in a small drop of salt water, altogether involving over a million atoms. This provided an unprecedented view into the dynamics of the virus for a very brief time, revealing nevertheless the key physical properties of the viral particle as well as providing crucial information on its assembly. It may take still a long time to simulate a dog wagging its tail in the computer, but a big first step has been taken to simulate living organisms. Naturally, this step will assist modern medicine (more on our satellite tobacco mosaic virus web page).