Biochemistry: Step Toward Life

Can chemists synthesize life? Not quite yet. But famed Biochemist Gerhard Schramm of the Max Planck Institute for Virus Research at Tubingen, Germany, is coming remarkably close. Last month he told a conference at Munich that he has managed with simple chemicals to build nucleic acid, the most vital compound in living organisms—and he used the same processes that are thought to have created the first life on earth.

Students of ancient life believe that billions of years ago the newly formed earth was covered by an atmosphere that had no free oxygen in it. Instead it had methane, ammonia, carbon dioxide and other gases that cannot be breathed by modern animals. Lightning flashes, so the theory goes, forced these gases to form complicated chemicals that dissolved in sea water. There the chemicals reacted with each other and the water, forming bigger and bigger molecules. After millions or billions of years of this process, a single molecule—perhaps a nucleic acid—was formed that had the ability to grow, reproduce and evolve into higher organisms.

This was the start of life, and chemists have often tried to copy the process themselves. They have mixed the proper gases in a laboratory flask, put water in the bottom to simulate the ocean, and shot electric sparks into it to do the work of the ancient lightning. When they analyzed the water, they found many an interesting chemical, some of them characteristic of living organisms, but they did not find nucleic acid, the essential substance at the heart of life.

Dr. Schramm started his synthesis with chemicals that were probably dissolved in the ancient ocean before life appeared. Some of them were simple sugars, amino acids or nucleotides (small molecules contained in nucleic acids). Perhaps the most important were phosphorus compounds called polyphosphate esters. Dr. Schramm believes that all of them could have been formed by natural, nonliving reactions on the lifeless earth.

Carefully avoiding life-made catalysts such as enzymes, he treated his chemical broth to moderate heat, pressure and other influences that were probably felt in the ancient ocean. Then he analyzed the product and found that it contained a simple nucleic acid. It met all chemical tests, and when its giant molecules were examined under a powerful electron microscope they showed evidence of the twisted, ropelike structure that is characteristic of natural nucleic acids.

Dr. Schramm wants no one to assume—as some German newspapers have done—that he expects soon to create real living creatures in his laboratory. His synthetic nucleic acid is not alive; it is merely chemically similar to the giant molecules that cluster in the nuclei of living cells and enable them to reproduce their kind. But he has brought chemistry closer to the day when some resourceful researcher will put together a molecule that can lead a dim, synthetic life.