The Search for Chiral Asymmetry as a Potential Biosignature in our Solar System

Glavin, Daniel P.; Burton, Aaron S.; Elsila, Jamie E.; Aponte, José C.; Dworkin, Jason P.

doi:10.1021/acs.chemrev.9b00474

Cited by 205 publications

(197 citation statements)

References 279 publications

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“…It is highly notable that, just like in the A‐12236 meteorite, racemic alanine coupled with similarly large l‐ aspartic acid and l‐ glutamic acid excesses ranging from ~25% to 60% have also been reported in the Murchison and Tagish Lake meteorites and an extraterrestrial origin for these amino acids and their l‐ excesses was firmly established by isotopic measurements that showed significant 13 C and 15 N enrichments relative to terrestrial organic matter (Engel and Nagy 1982; Engel and Macko 1997, 2001; Glavin et al. 2012, 2020a, 2020b). Based on carbon isotope measurements of d ‐ and l ‐glutamic acid extracted from a 1 g sample of the Murchison meteorite, Glavin et al.…”

Section: Resultsmentioning

confidence: 92%

“…2007; Pizzarello and Groy 2011; MacDermott 2012; Glavin et al. 2020a, 2020b). To date, no statistically significant d ‐enantiomeric excesses for amino acids with a single asymmetric carbon have been reported in any meteorite.…”

Section: Introductionmentioning

confidence: 99%

“…2007), while the solvent extractable organic matter represents a much smaller fraction of the organic carbon (up to ~0.1%) and is in the form of a wide variety of different compound classes that include amino acids, carboxylic acids, hydroxy acids, amines, alcohols, aldehydes and ketones, N‐heterocycles, polyols, aliphatic and aromatic hydrocarbons, sugars, and others (Glavin et al. 2018, 2020a; Furukawa et al. 2019).…”

Section: Introductionmentioning

confidence: 99%

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Abundant extraterrestrial amino acids in the primitive CM carbonaceous chondrite Asuka 12236

Glavin

McLain

Dworkin

et al. 2020

Meteorit & Planetary Scien

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The Asuka (A)-12236 meteorite has recently been classified as a CM carbonaceous chondrite of petrologic type 3.0/2.9 and is among the most primitive CM meteorites studied to date. Here, we report the concentrations, relative distributions, and enantiomeric ratios of amino acids in water extracts of the A-12236 meteorite and another primitive CM chondrite Elephant Moraine (EET) 96029 (CM2.7) determined by ultra-high-performance liquid chromatography time-of-flight mass spectrometry. EET 96029 was highly depleted in amino acids and dominated by glycine, while a wide diversity of two-to six-carbon aliphatic primary amino acids were identified in A-12236, which had a total amino acid abundance of 360 AE 18 nmol g À1 , with most amino acids present without hydrolysis (free). The amino acid concentrations of A-12236 were double those previously measured in the CM2.7 Paris meteorite, consistent with A-12236 being a highly primitive and unheated CM chondrite. The high relative abundance of a-amino acids in A-12236 is consistent with formation by a Strecker-cyanohydrin dominated synthesis during a limited early aqueous alteration phase on the CM meteorite parent body. The presence of predominantly free glycine, a near racemic mixture of alanine (D/L~0.93-0.96), and elevated abundances of several terrestrially rare nonprotein amino acids including a-aminoisobutyric acid (a-AIB) and racemic isovaline indicate that these amino acids in A-12236 are extraterrestrial in origin. Given a lack of evidence for biological amino acid contamination in A-12236, it is possible that some of the Lenantiomeric excesses (L ee~3 4-64%) of the protein amino acids, aspartic and glutamic acids and serine, are indigenous to the meteorite; however, isotopic measurements are needed for confirmation. In contrast to more aqueously altered CMs of petrologic types ≤2.5, no Lisovaline excesses were detected in A-12236. This observation strengthens the hypothesis that extensive parent body aqueous activity is required to produce or amplify the large L-isovaline excesses that cannot be explained solely by exposure to circularly polarized radiation or other chiral symmetry breaking mechanisms prior to incorporation into the asteroid parent body.

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Section: Resultsmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Abundant extraterrestrial amino acids in the primitive CM carbonaceous chondrite Asuka 12236

Glavin

McLain

Dworkin

et al. 2020

Meteorit & Planetary Scien

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“…Modern measurement strategies for life detection in extraterrestrial material have been discussed in detail elsewhere (e.g., Summons et al, 2008;Hand et al, 2017;Neveu et al, 2018;Glavin et al, 2019). In brief, they target multiple attributes (potential "biosignatures") that distinguish biological from abiotic properties or processes.…”

Section: Measurement Strategy and Sample Neededmentioning

confidence: 99%

Returning Samples From Enceladus for Life Detection

Neveu

Anbar

Dávila

et al. 2020

Front. Astron. Space Sci.

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Evidence suggests that Saturn's icy moon Enceladus has a subsurface ocean that sources plumes of water vapor and ice vented to space from its south pole. In situ analyses of this material by the Cassini spacecraft have shown that the ocean contains key ingredients for life (elements H, C, N, O and possibly S; simple and complex organic compounds; chemical disequilibria at water-rock interfaces; clement temperature, pressure, and pH). The Cassini discoveries make Enceladus' interior a prime locale for life detection beyond Earth. Scant material exchange with the inner Solar System makes it likely that such life would have emerged independently of life on Earth. Thus, its discovery would illuminate life's universal characteristics. The alternative result of an upper bound on a detectable biosphere in an otherwise habitable environment would likewise considerably advance our understanding of the prevalence of life beyond Earth. Here we outline the rationale for returning vented ocean samples, accessible from Enceladus' surface or low altitudes, to Earth for life detection. Returning samples allows analyses using laboratory instruments that cannot be flown, with decades or more to adapt and repeat analyses. We describe an example set of measurements to estimate the amount of sample to be returned and discuss possible mission architectures and collection approaches. We then turn to the challenges of preserving sample integrity and implementing planetary protection policy. We conclude by placing such a mission in the broader context of Solar System exploration.

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“…Chirality is one of the remarkable features in nature because a variety of molecular building blocks show intrinsic chiral preference and strict chiral selectivity, which has been the significant issue plaguing researchers exploring the origins of life . The enantiomers of a chiral molecule are stereoisomers that are non‐superimposable mirror images of each other .…”

Section: Introductionmentioning

confidence: 99%

A Chiral‐Label‐Free SERS Strategy for the Synchronous Chiral Discrimination and Identification of Small Aromatic Molecules

Wang

Zhao

et al. 2020

Angewandte Chemie

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Aversatile and robust chiral discrimination strategy for small aromatic compounds is of significant importance in multidisciplinary fields.H owever,m ost current methods lack either the sufficient sensitivity for recognizing the chirality of the target molecules or their molecular specificity information. We have developed av ersatile and chiral-label-free surfaceenhanced Raman scattering (SERS)-based chiral discrimination sensing system for small aromatic molecules,w here the molecular structural specificity and enantioselectivity can be given synchronously in asingle SERS spectrum. More than 10 types of chiral aromatic molecules were successfully identified by using this system. This work has enormous potential for recognizing chiral products effectively in sophisticated systems, especially in the fields of chiral synthesis and chiral catalysis.

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The Search for Chiral Asymmetry as a Potential Biosignature in our Solar System

Cited by 205 publications

References 279 publications

Abundant extraterrestrial amino acids in the primitive CM carbonaceous chondrite Asuka 12236

Abundant extraterrestrial amino acids in the primitive CM carbonaceous chondrite Asuka 12236

Returning Samples From Enceladus for Life Detection

A Chiral‐Label‐Free SERS Strategy for the Synchronous Chiral Discrimination and Identification of Small Aromatic Molecules

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