Levitt gave an overview of his research to KQED's Joshua Johnson this morning:

It’s research that started in 1967, so it’s research that’s been going on ever since I was 20 years old, so for 46 years. Basically, it tries to simulate the molecules of life. And simulation is now quite common — flight simulators and for bridges. I’m sure the Bay Bridge was simulated to pieces before it was built. So simulation is a very important tool. We started doing simulations on molecules back in the late ‘60s, principally because it had become clear that molecules had very well-defined shapes. They were complicated, they consisted of a thousand spheres, or a thousand atoms, and all these atoms were very precisely arranged.

This Stanford video explains how the work of Levitt and his Nobel colleagues benefits medicine, as researchers observe how protein molecules come together in ways that are healthy, or that promote disease. (Courtesy of Stanford University)

The molecules are much like the inside of a clock … they were all highly arranged in space. Once things are very arranged in space, you can do very precise calculations. You can simulate how they move, how they will behave under stress and so on. So it becomes a rather mechanical calculation, not exactly the same as simulating a jet airliner or a bridge or a nuclear explosion, but it’s a similar principal where you have a system and you see how it changes over time.

… This is something which ties in very closely to experiment because the shapes of these molecules were actually determined experimentally by crystallography, and that resulted in many Nobel Prizes--I guess in the early 1960s. Since then, it took a long, long time for people to appreciate that computation had a role to play. For me, the big excitement is to see computational biology honored in this way, because computers have had such a massive impact on everything else we do.

He also said simplicity in models remains crucial even though computer time, once a crushing research expense, has “become cheaper by a factor of 100 million or so.” Levitt said the computational representations of chemical processes he employs now are very similar to those he and his colleagues pioneered in the late ‘60s and early ‘70s.

Here's the summary of the trio's groundbreaking work from the Royal Swedish Academy of Sciences, which awards the Nobel in chemistry:

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.

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 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.

Michael LevittMichael Levitt

2013 Nobels: Stanford Biologist Shares Prize in Chemistry