Biologists spy close-up view of poliovirus linked to host cell receptor
WEST LAFAYETTE, Ind. - Researchers from Purdue and Stony Brook universities have determined the precise atomic-scale structure of the poliovirus attached to key receptor molecules in human host cells and also have taken a vital snapshot of processes leading to infection.
The virus binds to a receptor on the cell to form a single complex.
"This structure had been predicted, but the predictions were not as accurate as we had thought," said Michael Rossmann, Purdue's Hanley Distinguished Professor of Biological Sciences. "What we have now is the real structure, as opposed to a prediction of the receptor molecule. We also have a much higher resolution view of the complex of the receptor when bound to the virus."
The work was carried out by Ping Zhang, a Purdue doctoral student, and others working in Rossmann's laboratory in collaboration with the group at Stony Brook University in New York.
"These findings show the detailed relationship between atoms in the receptor and atoms in the virus," Rossmann said.
The research, which was funded by the National Institutes of Health, is not immediately geared toward medical applications. However, such findings might one day help scientists design better vaccines for the poliovirus and aid in research into the infection processes of other viruses, Rossmann said.
The findings are detailed in a research paper that appeared on Nov. 25 in the journal Proceedings of the National Academy of Sciences. MORE
New insights into microtubule dynamics and function in growth cones
Microtubules are cytoskeletal elements with important functions in cell division, organelle motility and cell movements. Dynamic microtubules are essential for guidance of the growth cone, the growing the tip of neuronal processes. However, the details of microtubule rearrangements and functions in growth cones have remained unclear. Studying the large growth cones of Aplysia californica neurons with Fluorescent Speckle Microscopy (FSM), the Suter lab has recently provided important new insights into both the mechanisms of microtubule rearrangements and their role in turnover of a key signaling molecule, Src tyrosine kinase. Live cell imaging of microtubule and actin dynamics during adhesion-mediated growth cone guidance revealed that microtubule reorganization is largely regulated by coupling to the actin cytoskeleton. Furthermore, microtubules mediate trafficking of Src in growth cones by supporting the retrograde retrieval of Src that has been endocytosed from the plasma membrane; thus, microtubules play a role in regulating the levels of active Src in the growth cone, which is important for growth cone turning. These studies have recently been published both as cover articles in Dev. Neurobiol., 68(12):1363-1377 by Lee and Suter and Mol. Biol. Cell. 19 (11):4611-27 by Wu et al.
2008 Biological Sciences Outstanding Alumni Named
Each year the Biological Sciences Department recognizes alumni who have achieved unusual success in their careers upon acquiring their degree(s) and leaving the corridors of Lilly Hall. This October Dr. Kuhn was privileged to honor three very distinctive and accomplished alumni: Dr. Steven Austad (Ph.D. ’81), Dr. Nancy W.Y. Ho (Ph.D. ’68) and Dr. Martha Twaddle Millar (B.S. ’81).
Steven N. Austad is a Professor in the Department of Cellular & Structural Biology and the Barshop Institute for Longevity & Aging Studies at the University of Texas Health Science Center San Antonio. His current research involves the search for ways to medically slow the rate of human aging. Dr. Austad became interested in the biology of aging during field research in Venezuela when he discovered to his surprise that opossums age remarkably fast. Before moving to Texas in 2004, he held faculty positions at the University of Idaho and Harvard University. Originally trained as an evolutionary field biologist, once Dr. Austad’s interest in the biology of aging was sparked by his discovery during field research in Venezuela that opossums lived no longer than mice.
His studies now involve bird and mammal species that our exceptionally long- or short-lived with the hope that understanding the physiological differences between these two groups will lead to novel therapies to enhance human health.
Nancy Ho is a research professor in the School of Chemical Engineering and a senior research scientist in the university's Laboratory of Renewable Resources Engineering. Dr. Ho is among 60 of the world's leading scientists, writers, artists, business and civic leaders whose essays were published in a new book edited by veteran TV journalist Mike Wallace, "The Way We Will be 50 Years from Today: 60 of the World's Greatest Minds Share Their Visions of the Next Half-Century,". Nancy led a team at Purdue that developed the more efficient yeast during the 1980s and 1990s. Conventional yeast can ferment glucose to ethanol, but it cannot ferment xylose. Xylose makes up about 30 percent of the sugar from agricultural residues, and the inability to ferment xylose would represent a major loss of ethanol yield. The Purdue researchers altered the genetic structure of the yeast so that it now contains three additional genes that make it possible to simultaneously convert glucose and xylose to ethanol. The ability to ferment xylose increases the yield of ethanol from straw by about 40 percent. Being able to simultaneously ferment glucose and xylose is important because both sugars are found together in agricultural residues.
Martha L. Twaddle, MD, FACP, FAAHPM, serves as Chief Medical Officer for Midwest Palliative & Hospice CareCenter formerly Palliative CareCenter & Hospice of the North Shore. A nationally recognized expert on palliative medicine, Dr. Twaddle has served as Hospice Medical Director since 1990 and became Chief Medical Officer as of May 2004. She is a Past President of the American Academy of Hospice and Palliative Medicine (AAHPM) and a Fellow of the American College of Physicians (ACP) as well as the AAHPM. Dr. Twaddle served on the Steering Committee and writing group of the National Consensus Project in Quality Palliative Care.
Congratulations to Dr. Austad, Dr. Ho & Dr. Twaddle Millar. Your success is a shining tribute to all Purdue Biological Sciences alumni and our current students; proving that a Biology Degree from Purdue University has far-reaching implications.
Sen. Lugar meets with Purdue biofuels researchers, tour labs and Purdue Research Park
U.S. Sen. Richard G. Lugar on Thursday (Oct. 9) met with Purdue University biofuels and alternative energy researchers and toured campus research facilities at Discovery Park and the Purdue Research Park.
The Republican senator heard presentations from biofuel, biotechnology and hydrogen storage researchers at Purdue's Laboratory for Renewable Resource Engineering (LORRE) and Birck Nanotechnology centers in Discovery Park. He also toured facilities at Swift Enterprises Ltd., a Purdue Research Park-based company developing a lead-free, alternative aviation fuel. Lugar met with Purdue President France A. Córdova and Victor L. Lechtenberg, vice provost for engagement, and joined a tour of research laboratories led by Alan Rebar, executive director of Purdue's Discovery Park.
Faculty Position in the Markey Center for Structural Biology Department of Biological Sciences Purdue University
The Department of Biological Sciences, Purdue University, invites applications for a tenure-track faculty position in Structural Biology associated with the Lucille P. Markey Center for Structural Biology (http://www-structure.bio.purdue.edu/). Potential areas of research interest include but are not limited to structural biology of viruses, bacterial pathogens, and membrane proteins. MORE
Structure Captures Toxin Peptide in Transit across a Membrane Channel Protein
A team of scientists led by Prof. W. A. Cramer, the Henry Koffler Distinguished Professor, has obtained a crystal structure of OmpF (“outer membrane protein F”), a major pore protein in the outer membrane of the E.coli bacterium, alone (see Figure) and in complex with a toxin peptide. OmpF serves as an aqueous conduit through the hydrophobic membrane, thereby allowing the bacteria to take up important nutrients necessary for its survival, and is a model structure for studies on the flow of water and solutes in the narrow channels that resemble nanotubes. The 1.6 Å resolution structure reveals the detailed distribution of water molecules within the trans-membrane channel. An additional structure of OmpF solved by the same team showed the OmpF pore to contain an unfolded protein fragment derived from a specialized “colicin E3” toxin. The structure confirms a previous hypothesis from the Cramer group that colicin toxins parasitize membrane receptors such as OmpF to enter the bacterial cell where they subsequently exert their cytotoxic effect. The toxin-porin structure is the first of its kind and provides a major advance in understanding of the mechanism of protein transfer across biological membranes. These studies were recently (August 6, 2008) published in the EMBO (European Molecular Biological Organization) Journal. Co-workers and co-authors were E. Yamashita (Institute of Protein Research, Osaka Univ., Japan), and M. V. Zhalnina,
Dr. S. D. Zakharov, and Dr. O. Sharma in the Dept. of Biological Sciences.
Spring issue of the BIONEWS hits the digital newsstand
Edwin Umbarger Distinguished Professor of Biology
Professor Stanton Gelvin was named the Edwin Umbarger Distinguished Professor of Biology at the Board of Trustees meeting on June 20, 2008.
Dr. Gelvin joined the Department of Biological Sciences at Purdue as an assistant professor in 1981, was promoted to associate professor in 1985, and full professor in 1991.
He has an international reputation for his work in the field of DNA transfer from the soil bacterium Agrobacterium tumefaciens to plant genomes. Dr. Gelvin has played a major role in developing the Agrobacterium system. This includes three main areas – the bacterium's processes, the expression of its transferred genes and the part the host plant plays in the transformation.