10.1021/acs.biochem.6b00255.s002
Raffaele Saladino
Raffaele
Saladino
Giorgia Botta
Giorgia
Botta
Bruno
Mattia Bizzarri
Bruno
Mattia
Bizzarri
Ernesto Di Mauro
Ernesto Di
Mauro
Juan Manuel Garcia
Ruiz
Juan Manuel
Garcia
Ruiz
A Global Scale Scenario for Prebiotic Chemistry: Silica-Based
Self-Assembled Mineral Structures and Formamide
American Chemical Society
2016
serpentinization reactions
Research Methods
membranous structures
Prebiotic Chemistry
metal silicate hydrate
space compartmentalization
N.H
chemical conditions
chemistry scenario
MSH membranes
De Yoreo
compounds results
abiotic route
MA
Proc
MgSO 4
Fe 2
NH 2 CHO
Biomineralization Science
ZnCl 2
prebiotic molecules
USA
Natl
carboxylic acids
Global Scale Scenario
Acad
Medicinal Chemistry
2016-04-26 00:00:00
Media
https://acs.figshare.com/articles/media/A_Global_Scale_Scenario_for_Prebiotic_Chemistry_Silica_Based_Self_Assembled_Mineral_Structures_and_Formamide/3207121
The
pathway from simple abiotically made organic compounds to the
molecular bricks of life, as we know it, is unknown. The most efficient
geological abiotic route to organic compounds results from the aqueous
dissolution of olivine, a reaction known as serpentinization (Sleep,
N.H., et al. (2004) <i>Proc. Natl. Acad. Sci. USA</i> 101,
12818–12822). In addition to molecular hydrogen and a reducing environment, serpentinization
reactions lead to high-pH alkaline brines that can become easily enriched
in silica. Under these chemical conditions, the formation of self-assembled
nanocrystalline mineral composites, namely silica/carbonate biomorphs
and metal silicate hydrate (MSH) tubular membranes (silica gardens),
is unavoidable (Kellermeier, M., et al. In <i>Methods in Enzymology,
Research Methods in Biomineralization Science</i> (De Yoreo,
J., Ed.) Vol. 532, pp 225–256, Academic Press, Burlington,
MA). The osmotically
driven membranous structures have remarkable catalytic properties
that could be operating in the reducing organic-rich chemical pot
in which they form. Among one-carbon compounds, formamide (NH<sub>2</sub>CHO) has been shown to trigger the formation of complex prebiotic
molecules under mineral-driven catalytic conditions (Saladino, R.,
et al. (2001) <i>Biorganic & Medicinal Chemistry</i>, 9, 1249–1253), proton irradiation (Saladino, R., et al.
(2015) <i>Proc. Natl. Acad. Sci. USA</i>, 112, 2746–2755),
and laser-induced dielectric breakdown (Ferus, M., et al. (2015) <i>Proc Natl Acad Sci USA</i>, 112, 657–662). Here, we show
that MSH membranes are catalysts for the condensation of NH<sub>2</sub>CHO, yielding prebiotically relevant compounds, including carboxylic
acids, amino acids, and nucleobases. Membranes formed by the reaction
of alkaline (pH 12) sodium silicate solutions with MgSO<sub>4</sub> and Fe<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>·9H<sub>2</sub>O show the highest efficiency, while reactions with CuCl<sub>2</sub>·2H<sub>2</sub>O, ZnCl<sub>2</sub>, FeCl<sub>2</sub>·4H<sub>2</sub>O, and MnCl<sub>2</sub>·4H<sub>2</sub>O showed lower
reactivities. The collections of compounds forming inside and outside
the tubular membrane are clearly specific, demonstrating that the
mineral self-assembled membranes at the same time create space compartmentalization
and selective catalysis of the synthesis of relevant compounds. Rather
than requiring odd local conditions, the prebiotic organic chemistry
scenario for the origin of life appears to be common at a universal
scale and, most probably, earlier than ever thought for our planet.