July 7, 2004

NSLS 2004 Annual Users’ Meeting Workshop

Anatomy of a Virus

It has been a memorable day at the workshop, “Anatomy of a Virus”, where prominent experts in the field got together to talk about their favorite subject. Sponsored by the User Executive Committee at the National Synchrotron Light Source, the National Institute of Health (National Institute of Allergy and Infectious Diseases, National Institute of General Medical Sciences, National Center for Research Resources) and Area Detector System Corporation (Poway, CA), this full day workshop was dedicated to highlight the frontiers in the study of viral structure and the future needs in Structural Virology. With the impressive list of speakers that were present on that day (front row of the picture), we all had the feeling that the future of Structural Virology was already there.

The workshop started with no less than an Historical Perspective given by Donald Caspar (Florida State University), which had been elegantly introduced by Dieter Schneider. Don related the important factors that were required for the success and the birth of structural studies of viral capsids. The next speaker was Denis Leclerc (Laval University) who reported on his progress on the assembly of nucleocapsid-like particles of Hepatitis C virus. Their results suggest that the first N-terminal half of the core protein would be sufficient for the formation of viral particles. Michael Chapman (Florida State University) presented his work on structural studies of a gene therapy vector, the Adeno-associated virus. From their atomic X-ray structure, it was possible to predict the viral site where it attaches to the cellular receptor. Huilin Li (Brookhaven National Laboratory) talked about the genomic RNA packaging in the Vesicular Stomatitis Virus. By single particle cryo-electron microscopy, a ring of density was revealed on the inner surface, and the density is proposed to be the RNA. Stacy Benson (the Wistar Institute) followed and reported on structural studies of the lipid-containing bacteriophage PRD1. The X-ray crystal structure of its major coat protein has revealed a molecule that contains two viral jelly rolls and appears to link PRD1 evolutionarily with the human adenovirus. Michael Rossmann (Purdue University) talked about: Membranes and Motors: Where Electron Microscopy Meets Crystallography. He described a variety of examples in which crystallography and cryoEM were combined to construct detailed atomic models of large complexes. A striking example was the structure of the bacteriophage T4 base plate assembly in two different states. High resolution structures of component proteins combined with cryoEM reconstructions of the entire base plate complex in the extended and contracted states revealed the extraordinary dynamic character of this complex and the large-scale motions of individual proteins.

The afternoon session started with Philip Dormitzer (Harvard Medical School) describing the structural rearrangements during Rotavirus cell entry. Their recent structure of the membrane penetration domain of VP4 reveals a fold-back rearrangement reminiscent of the enveloped virus fusion proteins that mediate enveloped virus cell entry. Wayne Hendrickson (Columbia University) gave his presentation on the structural biology of HIV attachment and entry into cells. His studies suggest that the flexibility of the glycoprotein GP120 of HIV is implicated in the escape to the immune response. The next talk: Motors and Membranes: Where Crystallography Meets Electron Microscopy was given by David Stuart (Oxford University). He presented his extensive work on the X-ray crystal structure analysis of the entire 66 MDa bacteriophage PRD1. These viral particles contain approximately 2000 protein subunits from 18 different protein species including integral membrane proteins associated with an internal lipid bilayer. Their crystal structure reveals, among other things, an ordered membrane structure that allows specific interactions with the genome and the coat proteins. John Johnson (The Scripps Research Institute) then closed the workshop with a lively talk about structure-based studies of auto-catalytic chemistry in virus particles. He described auto-catalytic cleavages that occur in the maturation of non-enveloped RNA insect viruses and proposed mechanisms based on atomic models from crystallography. The talk concluded with the description of a unique auto-catalytic ligation of a lysine side chain with an asparagine side chain to create catenated subunit rings that "chain-link" the capsid of HK97, a dsDNA bacteriophage.

ACKNOWLEDGEMENTS
I would like to thank the co-chair, Paul Freimuth (Biology Department, Brookhaven National Laboratory), for his help in organizing this workshop. The National Synchrotron Light Source is supported by the Department of Energy under contract #DE AC02-98CH10866.

FOR MORE INFORMATION
Marc Allaire
Building 725D
National Synchrotron Light Source
Brookhaven national Laboratory
Upton, NY
11973-5000
Tel.: (631) 344-4795
Fax: (631) 344-3238
Email: allaire@bnl.gov