Enantiomeric Enrichment on the Prebiotic Earth

Goldberg, Stanley I.

doi:10.1007/s11084-006-9016-7

Cited by 9 publications

(16 citation statements)

References 13 publications

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“…Others have proposed asymmetric adsorption of organic molecules onto mineral or crystal surfaces with handedness, such as calcite [132], as a geochemical route for the origin of homochirality. Enantiomeric enrichment from an initial imbalance can occur through physical [133,134] or chemical [135] amplification processes. Predominantly L-handed amino-oxazolines-precursors to RNA-are formed from the reaction of amino-oxazole with glyceraldehyde at a 1% excess of the L-enantiomer in the presence of chiral amino acids [136].…”

Section: Selectionmentioning

confidence: 99%

A Chemical Engineering Perspective on the Origins of Life

Grover

Hsieh

et al. 2015

Processes

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Atoms and molecules assemble into materials, with the material structure determining the properties and ultimate function. Human-made materials and systems have achieved great complexity, such as the integrated circuit and the modern airplane. However, they still do not rival the adaptivity and robustness of biological systems. Understanding the reaction and assembly of molecules on the early Earth is a scientific grand challenge, and also can elucidate the design principles underlying biological materials and systems. This research requires understanding of chemical reactions, thermodynamics, fluid mechanics, heat and mass transfer, optimization, and control. Thus, the discipline of chemical engineering can play a central role in advancing the field. In this paper, an overview of research in the origins field is given, with particular emphasis on the origin of biopolymers and the role of chemical engineering phenomena. A case study is presented to highlight the importance of the environment and its coupling to the chemistry.

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Section: Selectionmentioning

confidence: 99%

A Chemical Engineering Perspective on the Origins of Life

Grover

Hsieh

et al. 2015

Processes

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“…Goldberg showed, once seeded with one enantiomer, clay surfaces enhance selectivity for that enantiomer during crystallization cycles 20 . Recent experiments have pointed towards chirally selective adsorption and reactivity in clay mineral suspensions [21][22] .…”

Section: Introductionmentioning

confidence: 99%

Chiral interactions of histidine in a hydrated vermiculite clay

Fraser

Greenwell

Skipper

et al. 2011

Phys. Chem. Chem. Phys.

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Graphical Contents EntryWe report chiral differences in the effects of D-and L-histidine on the interlayer spacing of vermiculite clays that are relevant in assessing the role of clays in the origin of bio-homochirality. AbstractRecent work suggests a link between chiral asymmetry in the amino acid iso-valine extracted from the Murchison meteorite and the extent of hydrous alteration. We present the results of neutron scattering experiments on an exchanged, 1-dimensionally ordered n-propyl ammonium vermiculite clay. The vermiculite gel has a (001) d-spacing of order 5nm at the temperature and concentration of the experiments and the d-spacing responds sensitively to changes in concentration, temperature and electronic environment. The data show that isothermal addition of Dhistidine or L-histidine solutions produces shifts in the d-spacing that are different for each enantiomer. This chiral specificity is of interest for the question of whether clays could have played an important role in the origin of biohomochirality.

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“…In contrast, histidine solutions evolve in the opposite sense with D/L ratios increasing as histidine solutions are reacted sequentially with the vermiculite gels. To check this and to investigate the effect of reaction time, a fresh set of racemic histidine solutions was reacted with more fresh gel samples at four hour intervals and the results are also shown in Table 4 The 14 it is thus unlikely that the data presented here are the result of contamination of either the clays, or reagents used, with chiral L-amino acids originating in biological material.…”

Section: Resultsmentioning

confidence: 99%

“…To check this and to investigate the effect of reaction time, a fresh set of racemic histidine solutions was reacted with more fresh gel samples at four hour intervals and the results are also shown in Table 4 and The difference in behaviour of histidine solutions from alanine and lysine solutions is significant. Since it is known that once seeded with one enantiomer, clay surfaces enhance selectivity for that enantiomer during further crystallization cycles 14 it is thus unlikely that the data presented here are the result of contamination of either the clays, or reagents used, with chiral L-amino acids originating in biological material.…”

Section: Resultsmentioning

confidence: 99%

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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Enantiomeric Enrichment on the Prebiotic Earth

Cited by 9 publications

References 13 publications

A Chemical Engineering Perspective on the Origins of Life

A Chemical Engineering Perspective on the Origins of Life

Chiral interactions of histidine in a hydrated vermiculite clay

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

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