In the 1970s TV drama "The Six Million Dollar Man," the show's opening credits feature a team of scientists creating artificial limbs and an eye that, unlike today's prosthetic devices, could really work like the originals. Now scientists in real life are finally catching up--at least with photosynthetic bacteria. A paper in tomorrow's issue of Nature describes the first artificial cell that can turn light into biological energy.
Plants and other organisms, such as photosynthetic bacteria, convert sunlight into chemical energy that pumps protons into individual cells. Once the concentration of protons within a cell is high enough, they begin to diffuse back out through a gateway formed by ATP synthase. As the protons leave, they spur ATP synthase to make ATP--a molecule that serves as the fuel for all cells. For more than 20 years, chemists Thomas Moore, Ana Moore, and Devens Gust at Arizona State University in Tempe have been trying to mimic this elegant process. Now with the help of colleagues at the Institut Curie in Paris, France, they've succeeded.
In the 1980s the trio created a molecule that would pump protons into an artificial cell when inserted into its membrane and exposed to light. Now they've finally completed the crucial step--successfully equipping the cell with ATP synthase so the cell can produce ATP on its own. When they shined light on the bionic cell, it performed about as well as a natural plant cell would, converting 4% of the energy from the photons it absorbed to ATP.
"It's a wonderful paper," says James Hurst, a chemist at Washington State University in Pullman, Washington, who works in the same field. "This is a big step forward towards building artificial assemblies that can function as living cells," he adds. And the work could have major implications for the drug industry, says Hurst. Instead of using microbes to synthesize their compounds, he says, companies might be able to make compounds using artificial cells powered by solar energy.