Did lefty molecules seed life?

The molecular orientation of compounds brought to Earth by meteorites could have determined the world's chemistry long before life began, according to a new linkurl:study;http://www.pnas.org/cgi/doi/10.1073/pnas.0811618106 published online today (Mar. 16) in the __Proceedings of the National Academy of Sciences__. Artist's impression of the origins ofleft-handedness (click to enlarge)Image: NASA/Pat RawlingsAmino acids come in left-handed and right-handed forms, which, like a pair of human hand

Elie Dolgin
Mar 15, 2009
The molecular orientation of compounds brought to Earth by meteorites could have determined the world's chemistry long before life began, according to a new linkurl:study;http://www.pnas.org/cgi/doi/10.1073/pnas.0811618106 published online today (Mar. 16) in the __Proceedings of the National Academy of Sciences__.
Artist's impression of the origins of
left-handedness (click to enlarge)

Image: NASA/Pat Rawlings
Amino acids come in left-handed and right-handed forms, which, like a pair of human hands, are mirror images that cannot be superimposed onto each other. Yet living organisms use only the left-handed version, which presents a conundrum: There's no biochemical reason why one mirror image should be better than the other, so scientists have long debated whether life's left-handed leaning arose because of random processes or whether rocks from outer space seeded a southpaw solar system. The current study argues for the latter possibility by showing that some extraterrestrial meteorites contain an abundance of left-handed molecules....
Fragment of the Murchison meteorite
Image: US Department of Energy





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