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: Molecular Mechanism of Influenza Drug Resistance (Oct 2010)
Fever, chills, sore throat, coughing, aches, and pains? Ah ..... you have the flu! As a measure of prevention, vaccines against seasonal influenza are distributed and administered each fall. Last year though, the outbreak of the H1N1pdm "swine" influenza virus, caught health workers by surprise as this virus not only infected individuals during the spring and summer months, but also seemed to be particularly virulent towards otherwise healthy young people. Even more alarming was increasing evidence that H1N1pdm had acquired resistance to the frontline antiflu drug, Tamiflu. In response to this, computational biologists at the University of Illinois and the University of Utah teamed up to uncover the basis for influenza drug resistance through quantum chemistry, and molecular dynamics simulations with NAMD. The results of this study have recently been reported, and uncovered a two stage binding pathway for Tamiflu in H1N1pdm "swine" and H5N1 "avian" flu proteins, as well as a possible mechanism through which genetic mutations can induce drug resistance in one of the stages. Subsequent efforts at drug design against influenza can take advantage of this discovery. This discovery was made possible through use of so-called GPU computing (see Oct 2007 highlight "Graphics Processors Speed Up Simulations"). More information can be found here.