Non-racemic amino acids in the Murray and Murchison meteorites

Pizzarello, Sandra; Cronin, John R.

doi:10.1016/s0016-7037(99)00280-x

Cited by 300 publications

(242 citation statements)

References 48 publications

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“…Aqueous alteration is also related to the chiral excesses observed so that the β-alanine/AIB ratio correlates with the L/D chiral excess of isovaline. These data thus reaffirm and extend previous work on the correlation of enantiomeric excesses with aqueous alteration and the presence of hydrated phases in meteorite samples 17,28 .…”

Section: Introductionsupporting

confidence: 88%

Selective adsorption and chiral amplification of amino acids in vermiculite clay-implications for the origin of biochirality

Fraser

Fitz

Jakschitz

et al. 2011

Phys. Chem. Chem. Phys.

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Smectite clays are hydrated layer silicates that, like micas, occur naturally in abundance. Importantly, they have readily modifiable interlayer spaces that provide excellent sites for nanochemistry. Vermiculite is one such smectite clay and in the presence of small chain-length alkyl-NH 3 Cl ions, forms sensitive, 1-D ordered model clay systems with expandable nano-pore inter-layer regions. These inter-layers readily adsorb organic molecules. N-propyl NH 3 Cl vermiculite clay gels were used to determine the adsorption of alanine, lysine and histidine by chiral HPLC. The results show that during reaction with fresh vermiculite interlayers, significant chiral enrichment of either L-and D-enantiomers occurs depending on the amino acid. Chiral enrichment of the supernatant solutions is up to about 1% per pass. In contrast, addition to clay interlayers already reacted with amino acid solutions resulted in little or no change in D/L ratio during the time of the experiment. Adsorption of small amounts of amphiphilic organic molecules in clay inter-layers is known to produce Layer-by-Layer or Langmuir-Blodgett films. Moreover atomistic simulations show that self-organization of organic species in clay interlayers is important. These noncentrosymmetric, chirally active nanofilms may cause clays to act subsequently as chiral amplifiers, concentrating organic material from dilute solution and having different adsorption energetics for D-and L-enantiomers. The additional role of clays in RNA oligomerization already postulated by Ferris and others, together with the need for the organization of amphiphilic molecules and lipids noted by Szostak and others, suggests that such chiral separation by clays in lagoonal environments at normal biological temperatures might also have played a significant role in the origin of biochirality.2

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Section: Introductionsupporting

confidence: 88%

Selective adsorption and chiral amplification of amino acids in vermiculite clay-implications for the origin of biochirality

Fraser

Fitz

Jakschitz

et al. 2011

Phys. Chem. Chem. Phys.

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“…Prebiotic synthesis reactions, with the possible exception of some interstellar processes, yield essentially equal amounts of L-and D-enantiomers (1)(2)(3)(4). A significant challenge in origin-of-life research, therefore, is to identify natural mechanisms for the homochiral selection, concentration, and polymerization of molecules from an initially racemic mixture (5,6).…”

mentioning

confidence: 99%

Selective adsorption ofl- andd-amino acids on calcite: Implications for biochemical homochirality

Hazen

Filley

Goodfriend

2001

Proc. Natl. Acad. Sci. U.S.A.

362

261

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The emergence of biochemical homochirality was a key step in the origin of life, yet prebiotic mechanisms for chiral separation are not well constrained. Here we demonstrate a geochemically plausible scenario for chiral separation of amino acids by adsorption on mineral surfaces. Crystals of the common rock-forming mineral calcite (CaCO3), when immersed in a racemic aspartic acid solution, display significant adsorption and chiral selectivity of D-and L-enantiomers on pairs of mirror-related crystal-growth surfaces. This selective adsorption is greater on crystals with terraced surface textures, which indicates that D-and L-aspartic acid concentrate along step-like linear growth features. Thus, selective adsorption of linear arrays of D-and L-amino acids on calcite, with subsequent condensation polymerization, represents a plausible geochemical mechanism for the production of homochiral polypeptides on the prebiotic Earth.

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“…But compound specific isotopic measurements of 13 C and 15 N show that these excesses are not due to contamination [35,36]. This was further confirmed by the discovery of L-excess in non-protein chiral amino acids and in other meteorites [37,38]. Enantiomeric excesses are variable among meteorites [39], and also inside the same objects [40] but never exceed 18%.…”

Section: -P4mentioning

confidence: 75%

Organic and volatile elements in the solar system

Rémusat

2011

EPJ Web of Conferences

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Abstract. Chondrites and comets have accreted primitive materials from the early solar system. Those materials include organics, water and other volatile components. The most primitive chondrites and comets have undergone few modifications on their respective parent bodies and can deliver to laboratories components that were present at the origin of the protosolar nebula. Here I present a review of the organic material and volatile components that have been studied in the most primitive chondrites, and the last data from the stardust mission about the cometary record. This paper focuses on materials that can be studied in laboratories, by mass spectrometry, ion probes or organic chemistry techniques.

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Non-racemic amino acids in the Murray and Murchison meteorites

Cited by 300 publications

References 48 publications

Selective adsorption and chiral amplification of amino acids in vermiculite clay-implications for the origin of biochirality

Selective adsorption and chiral amplification of amino acids in vermiculite clay-implications for the origin of biochirality

Selective adsorption ofl- andd-amino acids on calcite: Implications for biochemical homochirality

Organic and volatile elements in the solar system

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