Don C. Wiley (1944–2001)

It was with great sadness that the structural biology community learned of the death of Don Wiley, one of the most prominent protein crystallographers of his generation. Don's research had a profound impact on many fields, including virology and immunology, with a series of elegant structural and biological studies of viruses and the immune response against them. Don started his scientific studies as a physics major at Tufts University, graduating in 1966. He switched to biophysics as a graduate student, joining William Lipscomb's laboratory at Harvard, at a time when the crystal structures of proteins were just beginning to be elucidated at atomic resolution. As a graduate student, Don set an ambitious goal for himself—to provide a structural explanation for the mechanism of allosteric regulation in aspartate transcarbamylase, resulting in a 5.5 A structure at a time when a project of this magnitude was virtually inconceivable.Don's graduate studies greatly impressed his colleagues, for he was hired as an assistant professor at Harvard immediately after earning his PhD in 1971. Steve Harrison was hired at about the same time, and the two young crystallographers set up a joint laboratory, sharing space, equipment, and supplies. Don soon decided to concentrate on structural studies of viral proteins, focusing on the influenza virus hemagglutinin. He contacted John Skehel, a British biochemist and virologist who had shown that hemagglutinin could be released from flu virus by bromelain treatment, resulting in a collaboration and friendship that lasted the rest of Don's life. With guidance from John, Don learned to grow flu virus in eggs and purify hemagglutinin, initially on his own and later during a sabbatical year spent in John's lab at Mill Hill. This immersion in the biological context surrounding the object of his structural studies was to mark Don's approach to all projects in his laboratory—it was not enough to solve a crystal structure of a protein; there had to be a reason for wanting to determine a structure, and Don's reasons related to wanting to answer fundamental questions involving human health. His faith in structure as the ultimate illuminator of function was fully realized by the completion of the hemagglutinin structure, published in 1981 by Don, John Skehel, and Don's first postdoc, Ian Wilson, which revealed a tall trimeric protein upon which the sites of viral antigenic shift and the host receptor binding region could be mapped. But the mechanism by which hemagglutinin accomplished fusion of the viral and host membranes remained unclear until a fusion-active structure was solved by Don's lab in 1994. This structure revealed a remarkable conformational change, suggesting a mechanism for juxtaposing the viral and host cell membranes. Don later expanded his interests to include other viral mediators of membrane fusion, including proteins from HIV and Ebola virus, revealing features in common with hemagglutinin, and was actively involved in the design of compounds to inhibit viral fusion.Figure 1Figure 1Figure 1View Large Image | View Hi-Res Image | Download PowerPoint SlideDon began the other major focus of his laboratory, the study of major histocompatibility complex (MHC) proteins and their recognition together with antigen by T cell receptors, in the late 1970s as a collaboration with his Harvard colleague Jack Strominger. Jack's laboratory had developed a method to purify the ectodomains of human class I MHC molecules from B lymphocytes, and these presented an intriguing target for crystallographic studies. At the time, the altered self hypothesis for MHC-restricted antigen recognition by T cells suggested by Rolf Zinkernagel and Peter Doherty's studies of T cell killing of virally infected cells raised the possibility that the mysterious dual recognition properties of T cells might be understood by taking the structures of a viral antigen (e.g., hemagglutinin) and an MHC protein (e.g., the human class I MHC molecule HLA-A2) and docking them together as a complex. Of course, we know now that T cells do not recognize intact viral antigens complexed with MHC molecules—instead, T cell receptors recognize peptide fragments of antigens bound to MHC proteins—but at the time Don's laboratory published the first MHC structure in 1987, the discovery of a peptide occupant in the HLA-A2 binding groove came as a big surprise. The fact that HLA-A2 contained a bound peptide (or peptides) demonstrated that T cell recognition of a virus or other pathogen in an infected cell was a lot more subtle than simply detecting the presence of a peptide antigen; since MHC molecules are always occupied with peptide, the T cell has to determine whether the peptide is derived from a safe “self” protein or from a dangerous “foreign” protein. Don followed up the HLA-A2 structure with structures of a number of other class I and class II MHC proteins, many with defined bound peptides, which allowed a complete description of the rules for peptide binding to class I and class II MHC proteins, culminating in the first high-resolution views of a T cell receptor/MHC/peptide complex, published in 1996.Don received many awards for his structural studies of viruses and how the immune system recognizes them, including the Lasker Award, the Japan Prize, and the Gairdner Foundation International Award. His contributions to structural virology and immunology will be sorely missed, as will his infectious love for science and for protein structures in particular. One of the things that made Don's laboratory a uniquely inspiring place to do research was Don's almost child-like enthusiasm for science. I especially remember his excitement over any new crystals, no matter how small or unpromising. This enthusiasm carried many of us through to successful completion of what might otherwise have seemed like hopeless projects. In my own case, working as a graduate student and then postdoc in Don's lab with thin microcrystals of HLA-A2, I might have given up had it not been for Don's unshakable confidence that not only would the structure be solved some day, but that when it was solved, it would be incredibly interesting. Don had the knack for making even the smallest step toward solving a structure seem like a breakthrough. For example, we spent some time analyzing the crystal packing at a time when I was having trouble with phasing, and Don was happy and excited to pore over the International Tables with me to figure out the relationship between the HLA-A2 space groups. In retrospect, this was not really very interesting, but Don made it seem fascinating. Not that working with Don was all sweetness and light—Don enjoyed trading insults with people, and his students were no exception. One he directed at me stands out in my mind—I had annoyed him with some now forgotten obnoxious graduate student behavior or comment, and exasperated, he told me that he hoped I would one day have a student exactly like me. I took this as an insult, as he had meant it, but implicit in the barb was that he was confident I would some day be in a position to have graduate students of my own, and it helped me through times when it seemed that I would never even earn a PhD.In my last conversation with Don, which took place at a meeting that ended the day before he disappeared in Memphis, he talked about his plans for the next 15 or so years. He had ambitious goals, such as solving the structure of an intact T cell receptor in a membrane with the CD3 components. He had also worked out how he would retire. Instead of continuing to run a laboratory, write grants, be responsible for students, etc. when he was in his 70s, he would do his own experiments in other people's labs. That way he would have the fun of doing science when he was older without all the responsibilities that running a laboratory entails. I had a vision of Don in 20 years' time, loudly and good-naturedly complaining about “cretins” and “toads” who had hidden his reagents or were trying to convince him to do an experiment in some stupid fashion (i.e., not the way it had been done with hemagglutinin), but having the time of his life back at the bench again. That's the way it should have been. Structural virology and immunology won't be the same without Don. Other labs may solve structures he would have solved, but no one else will achieve these goals with the same style and level of insight, appreciation, and awe that he had for the beauty revealed by protein structure.