A pair of Carnegie Mellon researchers have made a key discovery about amino acids, the most basic building blocks of life. For centuries, scientists have been perplexed by the fact that amino acids in living organisms exist exclusively in only one of two possible forms, or “enantiomers.” The researchers’ findings on how this may have come about in nature could also lead to the production of better pharmaceuticals, and were published in this week’s edition of Nature Chemistry.
“Pharmaceuticals are a 300 billion dollar industry, and rely on the ability to make one enantiomer in a drug, not a mixture of both,” said Andrew Gellman, the principle investigator of the study from the Department of Chemical Engineering at Carnegie Mellon. “If you make a drug that has both enantiomers and ingest it, one of them might be therapeutic, but the other probably isn’t. In fact it could be highly toxic.”
Enantiomers, commonly termed “left-” or “right-handed,” are molecules that are mirror images of each other, but they are not exact replicas and thus take on different properties when ingested by people or living organisms. When amino acids or pharmaceuticals are synthesized in laboratories, both enantiomers are produced and it is exceedingly difficult to separate the two.
But in this study, researchers were able to successfully produce a highly-purified mixture of “left-handed” enantiomers by reacting a gas consisting of slightly more “left-handed” enantiomers than “right-handed” ones with the surface of a piece of copper. This small initial imbalance was amplified after interacting with the copper surface, in spite of the fact that this copper surface is not “handed.”
“You could do this in a distillation-like process to make a substance more and more exclusively one-handed,” Gellman said. “This could be very useful for the pharmaceutical industry. But it also helps explain how the ‘primordial soup’ in which life began went in the direction of one-handedness.”
Source: Carnegie Mellon University