Billions of years ago, a simple amino acid may have triggered all other amino acids to adopt a left-handed configuration, determining the chemical fate of these biological building blocks and influencing the emergence of life on Earth.
Amino acids, the basic units of proteins, come in either right- or left-handed configurations–mirror images of each other. However, the amino acids in living organisms are all lefties. To find out why, R. Graham Cooks and his colleagues at Purdue University in West Lafayette, Ind., analyzed all 20 natural amino acids and found that only serine forms highly chemically stable clusters.
"Even more dramatic, the amino acids in each cluster were either all in the right or left form," says Cooks. In contrast, clusters of other amino acids were less stable and contained a mixture of both left and right configurations, Cooks and his colleagues report in the Aug. 4 Angewandte Chemie International Edition.