Physicsworld

Aug 11, 2003
Amino acid detected in space

The idea that primitive life on Earth may have been seeded by a comet or asteroid impact is controversial. Since it was suggested more than 40 years ago, however, increasingly complex organic molecules have been discovered in space. Now astronomers have detected an amino acid - one of the building blocks of proteins - in interstellar dust clouds in our galaxy. The discovery of glycine in space suggests that interstellar molecules may have played a pivotal role in the prebiotic chemistry of the Earth (Y-J Kuan et al. 2003 Astrophys. J. 593 848).

Glycine - CH2NH2COOH - is the simplest of all the 20 amino acids. Yi-Jehng Kuan of the National Taiwan Normal University and co-workers from the NASA Ames Research Center and the Polish Academy of Sciences searched for the molecule in the hot cores of three giant molecular clouds, which are regions of active star formation. They measured the spectral lines of the clouds - Sagittarius-B2, Orion-KL and W51 - over a four-year period using the 12-metre telescope at the National Radio Astronomy Observatory (NRAO) in Arizona.

The researchers claim that the discovery of glycine is the first step in establishing the crucial link between amino acids in space and the emergence of life in the solar system or, indeed, elsewhere in the galaxy. The molecular spectra seen in interstellar gas clouds closely matches those found in comets and meteorites, and comparing them could in principle allow astronomers - or exobiologists - to trace the origin of the Earth's early chemistry to its parent gas cloud.

Glycine is the simplest of all the amino acids and perhaps the easiest to form by abiotic processes...