Israeli professor Arieh Warshel on Wednesday won the Nobel Prize for Chemistry, along with fellow Jewish professors Michael Levitt (who also holds Israeli citizenship) and Martin Karplus.

Warshel, 72, is a distinguished professor of chemistry and biochemistry at the University of Southern California in Los Angeles, where he has been since the 1970s.

Fellow winner Michael Levitt, a South Africa-born professor, immigrated to Israel in 1979, married here and taught at the Weizmann Institute in Rehovot for most of the 1980s. Vienna-born Martin Karplus fled the Nazi occupation of Austria as a child in 1938.

Of the 23 chemistry Nobels awarded in the past decade, 11 of the winners were Jewish and six of them were Israelis. But both Warshel and Levitt left Israel for the US because they felt they could not progress here — Warshel did not get tenure at the Weizmann Institute — underlining concerns about the ongoing brain drain of top Israeli academics.

The trio won the award “for the development of multiscale models for complex chemical systems,” the Royal Swedish Academy of Sciences announced.

Warshel said the phone rang at 2 a.m. at his home in Los Angeles, and that “once I heard the Swedish accents,” he knew he’d won.

He said his research is motivated largely by his own curiosity. The work for which he and his colleagues were awarded the Nobel is for developing “a method that allowed us to understand how proteins actually work,” he said, and he explained that it was like seeing a watch, wondering what was going on inside, and finding out.

“We developed how a computer can take the structure of a protein, and can understand how it does exactly what it does — for example digesting food,” Warshel said. “You want to understand how it is happening, and then you can use it to design drugs, or in my case, to satisfy your curiosity,” the professor added.

Arieh Warshel (photo credit: CC BY Wikipedia)

Arieh Warshel (photo credit: CC BY Wikipedia)

Later Wednesday, Warshel said “I feel Israeli,” even though he has spent almost the past 40 years in the US and also has US citizenship. He told Army Radio he visits Israel often, and that his children speak Hebrew. “If Israelis want to define me as Israeli, that’s fine,” he said on Channel 2, sounding a little unsure. “I still define myself as Israeli, but it’s not a clear definition… I behave like an Israeli.”

Asked why he had left Israel for the US, he said it was “hard to progress at the Weizmann Institute.” He said he felt there was “still good science in Israel,” but “I know there are difficulties.”

Benny Warshel, his brother, told Israel Radio that Arieh brought great honor to the State of Israel. “He fought in this country’s wars, in the Six Day War and the Yom Kippur War, and he defends Israel in academic circles,” said Benny. “He’s very connected to this country,” he added.

Warshel was born in 1940 in Kibbutz Sde Nahum, in the Beit She’an Valley. He served in the IDF (reaching the rank of captain), then attended Haifa’s Technion, where he got a BSc degree in Chemistry in 1966. He earned MSc and PhD degrees in Chemical Physics (in 1967 and 1969), at the Weizmann Institute of Science in Rehovot. He then did postdoctoral work at Harvard University, returned to the Weizmann Institute in the early 1970s and also worked for the Laboratory of Molecular Biology, Cambridge, England. He joined the faculty of the Department of Chemistry at USC in 1976.

Michael Levitt (photo credit: CC BY Wikipedia)

Michael Levitt (photo credit: CC BY Wikipedia)

Levitt, who was born in Pretoria in 1947, received his BSc from King’s College, London and his PhD in computational biology from the University of Cambridge. He was a Royal Society Exchange Fellow at the Weizmann Institute from 1967-1968, immigrated to Israel in 1979 and was a professor of chemical physics at Weizmann from 1980-1987.

Levitt, too, left Israel because he felt professionally stymied. His sons live in Israel.

The third winner, Martin Karplus, was born in Vienna in 1930, and, along with his family, fled to the United States in 1938 to escape the Nazi occupation of Austria. He attended Harvard University and received his PhD from the California Institute of Technology. His daughter Rebecca is a family doctor in Jerusalem.

His brother Robert Karpus, who died in 1990, was also a theoretical physicist and was a professor at the University of California, Berkeley.

Martin Karplus (photo credit: courtesy Harvard University)

Martin Karplus (photo credit: courtesy Harvard University)

The Karpus family was “an intellectual and successful secular Jewish family” who were “prominent citizens” of Vienna, where there is a street named after them, according to “A Love of Discovery,” a biography of Robert Karpus published in 2002.

In its reasoning, the academy noted that in the past, chemists “used to create models of molecules using plastic balls and sticks. Today, the modelling is carried out in computers. In the 1970s, Martin Karplus, Michael Levitt and Arieh Warshel laid the foundation for the powerful programs that are used to understand and predict chemical processes.”

The academy continued, in a statement: “Computer models mirroring real life have become crucial for most advances made in chemistry today. Chemical reactions occur at lightning speed. In a fraction of a millisecond, electrons jump from one atomic nucleus to the other. Classical chemistry has a hard time keeping up; it is virtually impossible to experimentally map every little step in a chemical process. Aided by the methods now awarded with the Nobel Prize in Chemistry, scientists let computers unveil chemical processes, such as a catalyst’s purification of exhaust fumes or the photosynthesis in green leaves.”

It said the work of Karplus, Levitt and Warshel “is groundbreaking in that they managed to make Newton’s classical physics work side-by-side with the fundamentally different quantum physics. Previously, chemists had to choose to use either or. The strength of classical physics was that calculations were simple and could be used to model really large molecules. Its weakness, it offered no way to simulate chemical reactions. For that purpose, chemists instead had to use quantum physics. But such calculations required enormous computing power and could therefore only be carried out for small molecules.”

This year’s Nobel Laureates in chemistry, the academy said, “took the best from both worlds and devised methods that use both classical and quantum physics. For instance, in simulations of how a drug couples to its target protein in the body, the computer performs quantum theoretical calculations on those atoms in the target protein that interact with the drug. The rest of the large protein is simulated using less demanding classical physics. Today the computer is just as important a tool for chemists as the test tube. Simulations are so realistic that they predict the outcome of traditional experiments.”

Vienna-born Karplus is based at the Université de Strasbourg, France, and Harvard University, Cambridge, Massachusetts. Levitt, who holds UK and Israeli citizenship, works from Stanford University, California. Warshel, who holds US and Israeli citizenship, is a distinguished professor, University of Southern California, Los Angeles.

The prize amount, SEK 8 million — some $1.25 million — is to be shared equally between the laureates.