Abstract
The catalytic effects of complex minerals or meteorites are often mentioned as important factors for the origins of life. To assess the possible role of nanoconfinement within a catalyst consisting of montmorillonite (MMT) and the impact of local electric field on the formation efficiency of the simple hypothetical precursors of nucleic acid bases or amino acids, we performed ab initio Car–Parrinello molecular dynamics simulations. We prepared four condensed-phase systems corresponding to previously suggested prototypes of a primordial soup. We monitored possible chemical reactions occurring within gas-like bulk and MMT-confined four simulation boxes on a 20-ps time scale at 1 atm and 300 K, 400 K, and 600 K. Elevated temperatures did not affect the reactivity of the elementary components of the gas-like boxes considerably; however, the presence of the MMT nanoclay substantially increased the formation probability of new molecules. Approximately 20 different new compounds were found in boxes containing carbon monoxide or formaldehyde molecules. This observation and an analysis of the atom–atom radial distribution functions indicated that the presence of Ca2+ ions at the surface of the internal MMT cavities may be an important factor in the initial steps of the formation of complex molecules at the early stages of the Earth’s history.
Highlights
The origins of life theories are based on hypothetical chemical scenarios that lead to the formation of biomolecules, starting with substances that could be found in a given proto-earth-like system [1,2,3].These models share the assumption that there should be a way to explain the synthesis of complex biomolecules, starting from simpler molecular elements, and the notion that such a construction should happen in a scaled manner [4,5,6]
[39], given time required for the ab initio MD (AIMD) simulations of such large systems as those studied here (126–328 atoms)
We have addressed an intriguing question: To what extent does the confinement of the components of the hypothetical primordial soup affect the synthesis of new, more complex chemical compounds? We placed several test mixtures in the nanopores of the MMT mineral model, frequently considered as a catalyst in the formation of biology-related compounds
Summary
The origins of life theories are based on hypothetical chemical scenarios that lead to the formation of biomolecules, starting with substances that could be found in a given proto-earth-like system [1,2,3].These models share the assumption that there should be a way to explain the synthesis of complex biomolecules, starting from simpler molecular elements, and the notion that such a construction should happen in a scaled manner [4,5,6]. Despite still debated particular conditions present in the early Earth [7], formation of building blocks of life was possibly facilitated by appropriate physical factors such as reducing atmosphere, strong electric field, UV radiation, mineral catalytic surfaces, cometary impact, or high temperature [8]. Most of those theories meet at a point where simple substances, such as ammonia, carbon monoxide/dioxide, molecular oxygen, and water, form a molecular intermediate prior to the formation of nucleotides or amino acids [9]. After the Miller–Urey test, similar experiments were performed [1,2,16] showing richer chemistry, and even formation of nucleobases [17]
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