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Wet, carbonaceous asteroids undergo mineralogical changes and alter amino acids, affecting their structure and composition. Amino acids show symmetrical differences due to aqueous alteration, impacting their abundance and ratios. This study suggests implications for Earth's early history.
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Wet, Carbonaceous Asteroids: Altering Minerals, Changing Amino Acids + Water Aqueous alteration has substantially affected the mineralogy of many carbonaceous chondrites. An unaltered chondrule
Amino Acids Amino acids are characterized by the presence of an amine group, NH2, and a carboxylic acid group, COOH, joined to side chains (R). Two examples are shown. NASA /Mary Pat Hrybyk-Keith Amino acids also can have symmetrical differences in their structures, mirror images of each other. Shown are L-isovaline and D-isovaline.
Changes in the Amino Acid Mix with Aqueous Alteration Modified from Glavinet al., 2011. Increasing alteration causes the abundance of -Alanine to increase, others to decrease.
Changes in L/D with Aqueous Alteration Graphic prepared with data from Glavinet al. (2011). Aqueous alteration appears to have enriched isovaline in the L structure, suggesting that this could have happened on the early Earth or that carbonaceous chondrite asteroids added an already asymmetrical mix to the Earth.