Members of NAI's NASA Goddard Space Flight Center Team have a new paper in PNAS describing the distribution and enantiomeric composition of certain amino acids in carbonaceous meteorites. Their results show an increased amount of "left handed" isovaline in several meteorites, which helps to explain why all known life uses only left-handed versions of amino acids to build proteins.
"Finding more left-handed isovaline in a variety of meteorites supports the theory that amino acids brought to the early Earth by asteroids and comets contributed to the origin of only left-handed based protein life on Earth," said study co-author Danny Glavin.
The team also found a pattern to the excess. Different types of meteorites had different amounts of water, as determined by the clays and water-bearing minerals found in the meteorites. The team discovered that meteorites with more water also had greater amounts of left-handed isovaline.
[Source: NAI Newsletter]