When Martin Karplus was awarded the Nobel Prize in Chemistry, he was asked to describe his work in simple terms. "If you like to know how a machine works, you take it apart," he said. "We do that for molecules." In fact, Martin Karplus created the basis for computer-aided modeling of chemical processes that is now essential to understanding biomolecules such as proteins, DNA, RNA, and cell membranes.
Vienna was the first stop on his life's journey, but his departure from his hometown was not voluntary: after the "Anschluss" of Austria in 1938, the family fled first to Switzerland and then to the United States, where they built a new life in the Boston area. Contrary to the family tradition – both grandfathers were physicians, including the neurologist Johann Paul Karplus, a professor at the University of Vienna – Martin Karplus did not pursue a career in medicine. He was interested in the biological processes that underlie life and soon realized that these could only be understood in terms of the chemical and physical processes involved. He developed an approach that transcended the boundaries between disciplines and brought them together.
After completing his Ph.D. at the California Institute of Technology under the supervison of the future two-time Nobel laureate Linus Pauling and a postdoctoral fellowship at Oxford, Karplus received his first academic appointment at the University of Illinois. In 1959, he developed the "Karplus equation" named after him, which made it possible for the first time to derive the spatial structure of molecules from data obtained by nuclear magnetic resonance spectroscopy. After a stint at Columbia University, Martin Karplus returned to Harvard in 1966. There he devoted himself to developing models for studying the molecular dynamics of biological processes. His computer program Chemistry at Harvard Macromolecular Mechanics (CHARMM), published in 1983, continues to be developed and used until today, including at the Institute of Computational Biological Chemistry at the University of Vienna.
In 2013, Martin Karplus shared the Nobel Prize in Chemistry with Arieh Warshel and Michael Levitt for his pioneering contributions to the development of multiscale models of complex chemical systems. In 2015, the Republic of Austria honored him with the Austrian Decoration of Honor for Science and Art, and the University of Vienna awarded him an honorary doctorate on the initiative of the Faculty of Chemistry. A selection of travel photos of the passionate photographer were also exhibited on this occasion. Last August, Martin Karplus was awarded the Grand Decoration of Honor in Gold for Services to the Republic of Austria, one of the country's highest honors.
The author of this obituary would like to add a personal note: In 1990 I went to Harvard as a graduate student to study with one of the best theoretical chemists. In fact, Martin Karplus became my scientific mentor. Like many other "Karplusians," I asked myself more than once: How would Martin approach this question? Almost more important for me, however, was to get to know him over all the years that we were in contact, and to appreciate him as a man of many facets who was truly a role model, both as a scientist and as a fellow human being.
At the beginning of his Nobel Prize acceptance speech, Martin Karplus quoted Ralph Waldo Emerson: Do not go where the path may lead, go instead where there is no path and leave a trail. Martin Karplus has certainly succeeded in leaving a trail, both in science and in the lives of his colleagues and students.
An obituary by Stefan Boresch.
