4 Americans, German Share Science Nobels

Two American molecular biologists who revolutionized scientists’ view of the nature of the first life on Earth won the Nobel Prize for chemistry on Thursday, while two Americans and a German physicist who developed new techniques for highly accurate timekeeping shared the physics Nobel.

Thomas Cech of the University of Colorado in Boulder and Sidney Altman of Yale University will share the $460,000 chemistry prize for their unexpected discovery that ribonucleic acid (RNA), which was originally thought only to be a repository of genetic information, can carry out biochemical functions as well. The discovery may make possible new ways to fight the common cold and other viruses.

Norman Ramsey of Harvard University will receive half the physics prize for his discovery of the atomic clock, which utilized the element cesium to make modern timekeeping possible and, in the process, helped develop a firm underpinning for relativity, one of the most esoteric theories in physics.

Hans G. Dehmelt of the University of Washington in Seattle and Wolfgang Paul of the University of Bonn in West Germany shared the other half for their development of techniques for trapping charged particles for long periods of time, which is expected to lead to the development of clocks that are many times more accurate than even the cesium clocks.

The announcements completed a near-sweep of the science Nobels by U.S. researchers this year, continuing U.S. dominance of the prizes. On Monday, cancer researchers Harold E. Varmus and J. Michael Bishop of UC San Francisco were named winners of the medicine Nobel, making six of the seven recipients Americans.

All the new laureates expressed surprise and delight upon their early morning notification of the awards. “I would not say I expected it,” Dehmelt said, “but I may have hoped or wished for it.”

“It was something that everyone has been telling me would happen,” Cech said, “but I had no way of knowing when.”

At a morning celebratory party at Harvard, Ramsey poured champagne for two previous Harvard Nobel laureates and, before pouring his own glass, paused and said: “Well, my day is probably shot anyway.”

Asked about his plans for the prize money, Dehmelt said: “I will spend it.”

Cech, 41, and Altman, 50, helped evolutionary biologists attack an age-old puzzle that is often stated in terms of the riddle, “Which came first, the chicken or the egg?” In this case, the “egg” is deoxyribonucleic acid (DNA), the genetic blueprint that stores all the information from which organisms are constructed, while the “chickens” are proteins, which carry out all biochemical functions in the cell.

Biologists reasoned that the first life on Earth had to have both genetic information and biochemical functions, implying that both DNA and proteins must have been present when the first life arose from the primordial ooze. But virtually everyone agrees that a system containing both DNA and proteins is too complex to have arisen spontaneously, leaving researchers at an impasse.

Cech and Altman, working independently, solved the problem by focusing on RNA, which until that time had been considered only a simple messenger--in effect, a set of working blueprints, copied from the master blueprint of DNA, that serve as a pattern for the construction of proteins.

In 1978, the Canadian-born Altman was studying an RNA-cutting protein from a bacterium when he found that RNA fragments were necessary for the activity of the protein. Altman himself had difficulty believing his results and even greater difficulty publishing them. Funding agencies were also highly skeptical about his claims.

But in 1981, Cech, who received his doctorate from UC Berkeley, demonstrated that the cutting and splicing of RNA from a single-celled protozoan could be carried out in the absence of proteins. He and Altman subsequently showed that RNA could take the place of proteins called enzymes in carrying out many chemical reactions, opening a floodgate of new research on RNA.

But researchers also believe that the concept of RNA enzymes will have even greater importance in the future because they might be used to destroy viruses or to remove the genetic information that makes them harmful, leading to new treatments for disease.

Although not as old as the origin of life, the problem of keeping time has plagued humans for eons. From the beginning of time until 1967, timekeeping methods were based on the rotation of the Earth.

In that year, the world switched to a newer form of timekeeping based on the oscillations of cesium atoms in a so-called atomic clock. That clock was largely the work of Ramsey, 74.

In essence, Ramsey found a way to measure the frequency with which cesium atoms, flying through a cavity, switch between two electronically excited states. Since 1967, one second has been defined internationally as the time required for 9,192,631,770 such oscillations.

The chief advantage of the atomic clock is that it is accurate to one second in 300,000 years.

Precise timekeeping is crucial in a variety of modern applications. In satellite-based navigation systems, for example, the time required for a radio signal to travel to a ship or plane from satellites can be used to determine position precisely, but only if the timekeeping is accurate. Deep space communications also require extremely stable frequencies such as those produced by atomic clocks.

The new clocks have also been crucial in confirming Einstein’s Theory of General Relativity, which predicts, among other things, that time passes faster when gravity is lower, but more slowly for objects traveling at high speed.

But the differences are so small that high accuracy is required. In one experiment, for example, a cesium clock was carried in an airplane flying at 30,000 feet for 15 hours. When the plane landed, the clock had gained about 45 billionths of a second, confirming the theory.

But the accuracy of atomic clocks is limited by the necessity of measuring the oscillations of the fast-moving cesium atoms, a problem akin to taking a clear photograph of a speeding bullet.

The 57-year-old Dehmelt, a naturalized citizen born in Germany, and Paul, 76, devised techniques for trapping single cesium ions (atoms from which an electron has been stripped away) or other charged particles in magnetic fields for long periods of time.

Using these techniques, researchers at the National Institute of Standards and Technology, the nation’s official timekeeper, are now developing clocks that are 100,000 times as accurate as existing cesium clocks.