RNA researchers earn chemistry Nobel.

RNA researchers earn chemistry Nobel

For basic biochemical studies that have opened windows onto ancient life and that one day could spawn practical payoffs such as antiviral therapies, two U.S. scientists will share this year's Nobel Prize in Chemistry.

The Karolinska Institute in Stockholm, Sweden, last week named chemist Thomas R. Cech of the University of Colorado in Boulder and Canadian-born molecular biologist Sidney Altman of Yale University as recipients of the award for their independent discoveries that ribonucleic acid (RNA) not only passively carries genetic information in living cells, but also performs active enzyme-like functions. Their work toppled the dogma that proteins held a complete monopoly in biochemical catalysis. Moreover, scientists trying to understand how life began now look to catalytic RNA molecules, or ribozymes, as likely biochemical ancestors that evolved into the DNA-RNA-protein progression of modern cells (SN: 6/17/89, p. 372).

"That RNA can act as an enzyme is one of the more important findings in chemistry in the last decade or maybe two," comments molecular biologist Gerald F. Joyce of the Research Institute of Scripps Clinic in La Jolla, Calif. "When you hear 'enzyme,' you reflexively think of protein" and not RNA, he says. "Maybe this Nobel Prize will liberalize people's thinking about what an enzyme is."

While studying common bacterial cells in the late 1970s and early 1980s, Altman found an unusual enzyme made of both protein and RNa components. At first he regarded the unexpected RNA as a contaminant. But Altman found that separating the complex's two components destroyed its enzymatic function, showing for the first time that RNA was necessary for the enzyme to work. By 1983 Altman and his colleagues showed that RNA alone (under complex test-tube conditions) can function as an enzyme. In cells, enzymatic activity probably requires protein as well as RNA, he says.

At about the same time, Cech discovered that certain RNA molecules in single-celled organisms called Tetrahymena thermophila are capable of unassisted catalytic activity in test tubes. He found that the RNA could cut away extraneous segments of itself and then splice its remaining fragments into a genetically more meaningful RNA molecule. In 1982, he published the first account of such catalytic RNA molecules.

Joyce says the work of Cech and Altman has led to a new scientific field called RNA enzymology and may lead to new biotechnologies with payoffs as grand as curing the common cold.