Viruses
Viruses are small intracellular parasites that invade the cells of virtually all known organisms. They reproduce by utilizing the cell's machinery to replicate viral proteins and genomic material, generally damaging or killing the host cell in the process; subsequentelly, a large number of newly generated viruses go on to infect other cells. Viruses are responsible for a wide variety of human diseases, ranging from the common (influenza and colds) to the exotic (AIDS, West Nile virus and Zika). Some viruses which are not dangerous to humans can also be exploited in technological applications, in addition, viruses find use in genetic engineering applications and increasingly in the design of new nanomaterials. At the very least, all viruses contain two components: the capsid (a protein shell), and a genome, consisting of either DNA or RNA. Some viruses also include accessory proteins to aid in infection, and in some cases a lipid bilayer to further protect their contents from the environment. The viral life cycle itself is deceivingly simple: viruses enter the cell, typically (but not always) through the interaction of their capsid with a receptor on the cell surface; the virus must then somehow disassemble its capsid to release its genetic material and any necessary helper proteins. The viral genome is then replicated and the proteins it codes for are synthesized to produce the raw material for the production of new viral particles; these new viruses then assemble and bud from the cell either through the membrane or upon cell death.
Spotlight: Good News for the Easter Bunny (Apr 2013)
Rabbit hemorrhagic disease is extremely contagious and associated with liver necrosis, hemorrhaging, and high mortality in adult rabbits. First described in China in 1984, within a few years, rabbit hemorrhagic disease spread to large parts of the world and today threatens the rabbit industry and related ecology. The disease is caused by a virus, aptly named rabbit hemorrhagic disease virus. As reported recently, a group of experimental and computational researchers combining crystallography, electron microscopy and data-guided molecular dynamics simulations utilizing NAMD determined an atomic model of the capsid, namely the protein shell that surrounds the genetic material of the virus. The capsid simulations involved 10 million atoms and have become feasible only through Blue Waters, a brand new petascale supercomputer. The atomic model, analyzed by means of VMD, recently adapted to studies of very large structures, resolves the structural framework that furnishes both mechanical protection to the viral genes as well as a quick release mechanism after a virus enters a host cell. Researchers can use the detailed knowledge of the capsid structure to develop vaccines against rabbit hemorrhagic disease. More information is available on our virus website and in a news story.
