title: Meteoritic Amino Acids: Diversity in Compositions Reflects Parent Body Histories.
abstract: The analysis of amino acids in meteorites dates back over 50 years; however, it is only in recent years that research has expanded beyond investigations of a narrow set of meteorite groups (exemplified by the Murchison meteorite) into meteorites of other types and classes. These new studies have shown a wide diversity in the abundance and distribution of amino acids across carbonaceous chondrite groups, highlighting the role of parent body processes and composition in the creation, preservation, or alteration of amino acids. Although most chiral amino acids are racemic in meteorites, the enantiomeric distribution of some amino acids, particularly of the nonprotein amino acid isovaline, has also been shown to vary both within certain meteorites and across carbonaceous meteorite groups. Large l-enantiomeric excesses of some extraterrestrial protein amino acids (up to ∼60%) have also been observed in rare cases and point to nonbiological enantiomeric enrichment processes prior to the emergence of life. In this Outlook, we review these recent meteoritic analyses, focusing on variations in abundance, structural distributions, and enantiomeric distributions of amino acids and discussing possible explanations for these observations and the potential for future work.
authors.affiliation: Solar System Exploration Division, NASA Goddard Space Flight Center , Greenbelt, Maryland 20771, United States.
authors.forename: Jamie E
authors.initials: JE
authors.lastname: Elsila
authors.affiliation: Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, United States; Department of Chemistry, Catholic University, Washington, D.C. 20064, United States.
authors.forename: José C
authors.initials: JC
authors.lastname: Aponte
authors.affiliation: Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States.
authors.forename: Donna G
authors.initials: DG
authors.lastname: Blackmond
authors.affiliation: Astromaterials Research and Exploration Science Division, NASA Johnson Space Center , Houston, Texas 77058, United States.
authors.forename: Aaron S
authors.initials: AS
authors.lastname: Burton
authors.affiliation: Solar System Exploration Division, NASA Goddard Space Flight Center , Greenbelt, Maryland 20771, United States.
authors.forename: Jason P
authors.initials: JP
authors.lastname: Dworkin
authors.affiliation: Solar System Exploration Division, NASA Goddard Space Flight Center , Greenbelt, Maryland 20771, United States.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Glavin