Nobel Chemistry: Laureates’ techniques enable researchers to probe large biomolecules

The 2002 Nobel Prize in Chemistry, awarded Oct. 9, recognizes the work of three scientists who created tools for analyzing proteins and other large biological molecules.

The techniques developed by these laureates have transformed pharmaceutical development by enabling researchers to quickly determine the identities and structures of molecules that are central to countless biological processes. The techniques also hold promise for many other applications, such as analyzing food and diagnosing disease.

“I think that this [award] demonstrates the centrality of chemistry,” comments analytical chemist Catherine Fenselau of the University of Maryland in College Park.

“Their inventions have enabled biology, biotechnology, and molecular biology.”

John B. Fenn of the Virginia Commonwealth University in Richmond shares half of the prize with Koichi Tanaka of Shimadzu Corp. in Kyoto, Japan. The other half goes to Kurt Wüthrich of the Swiss Federal Institute of Technology in Zurich and the Scripps Research Institute in La Jolla, Calif.

“I got rudely awakened this morning at 5:30, and the phone hasn’t stopped ringing since,” Fenn told Science News on Oct. 9. “I’m still in a daze about it.”

Fenn and Tanaka each developed a way to apply a common analytical technique, mass spectrometry, to large biological molecules. Mass spectrometry, which identifies chemicals based on their masses, has been used for nearly a century. But until Fenn’s and Tanaka’s contributions in the late 1980s, researchers could use the technique only to identify small-or medium-size molecules.

With mass spectrometry, molecules’ masses are determined by how fast they travel in a vacuum chamber. Before this procedure can work for large biomolecules, however, they must be separated from one another into gaseous, electrically charged ions–without destroying their structures in the process. Fenn developed a method to do this by spraying a solution through an aperture in the presence of a strong electric field. In contrast, Tanaka’s technique uses a laser pulse to blast a solid or viscous sample, releasing charged molecules from the substance.

Wüthrich’s work focused on another common laboratory technique, which reveals molecules’ three-dimensional structures. Called nuclear magnetic resonance (NMR), it gives detailed pictures by indicating atoms’ relative positions in a molecule. But like mass spectrometry, this technique until recently had only worked on small molecules. Then, in the 1980s, Wüthrich developed a new method for determining which peaks in complicated NMR spectra are associated with particular atomic nuclei.

He also worked out a technique for using this information to calculate the 3-D structures of large, complex molecules.

X-ray diffraction techniques have provided 3-D structures for crystallized proteins for almost 50 years. Yet until Wüthrich’s NMR advances, the molecules couldn’t be visualized in solution, which more closely mimics the natural, cellular milieu of biomolecules.

“We’re pleased that there is an analytical award,” says mass spectroscopist Robert Cotter of Johns Hopkins University in Baltimore. “People tend to think of us as just the practitioners of methods and not [as scientists who make] fundamental contributions.”


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