Wider range of asteroids could have made life's ingredients

Washington, Jan 19 (ANI): A new NASA research has suggested that a wider range of asteroids were capable of creating the kind of amino acids used by life on Earth.

In March 2009, researchers at NASA's Goddard Space Flight Center in Greenbelt found an excess of the left-handed form of the amino acid isovaline in samples of meteorites that came from carbon-rich asteroids.

The discovery suggested that perhaps left-handed life got its start in space, where conditions in asteroids favored the creation of left-handed amino acids. Meteorite impacts could have supplied this material, enriched in left-handed molecules, to Earth.

In the new research, the team has reported that finding excess left-handed isovaline (L-isovaline) in a much wider variety of carbon-rich meteorites.

"This tells us our initial discovery wasn't a fluke; that there really was something going on in the asteroids where these meteorites came from that favors the creation of left-handed amino acids," said Daniel Glavin of NASA Goddard.

L-isovaline excesses in these additional water-altered type 1 meteorites (i.e. CM1 and CR1) has suggested that extra left-handed amino acids in water- ltered meteorites are much more common than previously thought, according to Glavin.

Now the question is what process creates extra left-handed amino acids. There are several options, and it will take more research to identify the specific reaction, according to the team.

However, "liquid water seems to be the key. We can tell how much these asteroids were altered by liquid water by analyzing the minerals their meteorites contain. The more these asteroids were altered, the greater the excess L-isovaline we found. This indicates some process involving liquid water favors the creation of left-handed amino acids," said Galvin.

Another clue comes from the total amount of isovaline found in each meteorite. "In the meteorites with the largest left-handed excess, we find about 1,000 times less isovaline than in meteorites with a small or non-detectable left-handed excess. This tells us that to get the excess, you need to use up or destroy the amino acid, so the process is a double-edged sword," added Glavin.

The findings were published online in Meteoritics and Planetary Science. (ANI)

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