Nobel Prize winner Martin Karplus, professor emeritus of chemistry at Harvard University, delivered the Oncley Lecture in Biophysics at the Rackham Amphitheater on Friday.  

Karplus received the Nobel Prize in Chemistry in 2013 with Stanford Biology Prof. Michael Levitt and Arieh Warshel, a chemistry professor at the University of Southern California, for their work on computational simulations.

In a talk titled “Motion: The Hallmark of Life. From Marsupials to Molecules,” Karplus explained how the motion of molecules makes the motion of entire animals possible.

He began by quoting physicist Richard Feynman’s “Lectures on Physics,” which emphasized the importance of understanding the motion of atoms and molecules in understanding the motion of living organisms: “Everything that living things do can be understood in terms of the jiggling and wiggling of atoms.”

He pointed out several different applications of understanding how molecules move — applications made possible in part by the computation simulations for which he and his colleagues received the Nobel Prize.

The simulations, which Karplus, Levitt and Warshel began in the 1970s, developed an easier method to replicate chemical reactions using computers. Prior to their work, chemists had to use advanced calculations based on quantum physics to simulate reactions. Because the calculations were so complex, the simulations required enormous computing power, meaning chemists could only simulate the reactions of small, simple molecules.

To address this issue, Karplus said he and his colleagues combined quantum physics with the simpler, less computationally demanding Newtonian physics to simulate chemical reactions for more complex molecules.

They discovered that while quantum physics is required for simulating chemical reactions at the specific site on the molecules where the reaction occurs, the simpler Newtonian physics could be used for simulating the impact of the reaction on the rest of the molecule. Quantum mechanics studies the activity going on inside an atom.

The computational simulations discovered by Karplus and his colleagues are now frequently used in multiple spheres of chemistry research, such as simulating how synthetic drugs interact with proteins in a person’s body and how defective proteins behave differently from normal proteins.

Karplus said he would like to simulate more complex biological systems in the future, such as the brain, viruses and cells, to complement the more typical kind of chemistry experiments carried out in a test tube.

“Experimentalists can use simulations as a tool,” Karplus said.

Chemistry Prof. Charlie Brooks, who worked as a postdoctoral scholar under Karplus’ supervision and hosted the Harvard professor during his visit, noted that science isn’t Karplus’ only interest. Brooks said as a Harvard professor, Karplus spent summers cooking at three-star restaurants throughout France.

“He is an image of a real Renaissance individual,” Brooks said.

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