Acceleration of amino acid racemization by isovaline: possible implications for homochirality and biosignature search
| العنوان: | Acceleration of amino acid racemization by isovaline: possible implications for homochirality and biosignature search |
|---|---|
| المؤلفون: | Stefan Fox, Annika Gspandl, Franziska M. Wenng |
| المصدر: | International Journal of Astrobiology. 19:276-282 |
| بيانات النشر: | Cambridge University Press (CUP), 2020. |
| سنة النشر: | 2020 |
| مصطلحات موضوعية: | chemistry.chemical_classification, Physics and Astronomy (miscellaneous), 010405 organic chemistry, 01 natural sciences, 0104 chemical sciences, Amino acid, chemistry.chemical_compound, chemistry, Isovaline, Space and Planetary Science, 0103 physical sciences, Biosignature, Earth and Planetary Sciences (miscellaneous), Organic chemistry, Amino acid dating, sense organs, Homochirality, Enantiomer, Chirality (chemistry), 010303 astronomy & astrophysics, Racemization, Ecology, Evolution, Behavior and Systematics |
| الوصف: | In nature, abiotically formed amino acids are usually racemic. However, this is not true for the α,α-dialkyl amino acid isovaline (Iva), which has an L-enantiomeric excess in some specimens of carbonaceous meteorites. On the early Earth and Mars, such meteorites were sources of amino acids, including Iva. Therefore, a connection may exist between the possible chiral influence of non-racemic Iva and the origin of biological homochirality. On the surface of a young terrestrial planet, amino acids can be chemically altered in many ways. For example, high temperatures from geothermal heating can lead to racemization. Four billion years ago, active volcanism and volcanic islands provided suitable conditions for such reactions and perhaps even for early microbial life on Earth. In the current study, we investigated the influence of D- and L-Iva on the thermal racemization of L-alanine (L-Ala) and L-2-aminobutyric acid (L-Abu) in a simulated hot volcanic environment. The amino acids were intercalated in the clay mineral calcium montmorillonite (SAz-1). While Iva was resistant to racemization, partial racemization was observed for Ala and Abu after 8 weeks at 150°C. The experimental results – for example, accelerated racemization in the presence of Iva and different influences of the Iva enantiomers – suggest that the amino acid molecules interacted with each other, possibly in hydrogen-bonded dimers. Accelerated racemization of amino acids could have been an obstacle to the development of homochirality. Besides, it is also detrimental to the use of homochirality as a biosignature, for example, in the search for microbial life on Mars. |
| تدمد: | 1475-3006 1473-5504 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::0bb96f6c0f27fbd6ce6d13908df50a36 https://doi.org/10.1017/s1473550420000014 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi...........0bb96f6c0f27fbd6ce6d13908df50a36 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 14753006 14735504 |
|---|