scholarly journals Metals likely promoted protometabolism in early ocean alkaline hydrothermal systems

2019 ◽  
Vol 5 (6) ◽  
pp. eaav7848 ◽  
Author(s):  
Norio Kitadai ◽  
Ryuhei Nakamura ◽  
Masahiro Yamamoto ◽  
Ken Takai ◽  
Naohiro Yoshida ◽  
...  
Keyword(s):  
Tricarboxylic Acid Cycle ◽  
Hydrothermal Systems ◽  
Metal Sulfides ◽  
Hydrogen Electrode ◽  
Metal Production ◽  
Threshold Potential ◽  
Hydrothermal Processes ◽  
Autotrophic Metabolism ◽  
The Origin Of Life ◽  
Reductive Tricarboxylic Acid Cycle

One of the most plausible scenarios of the origin of life assumes the preceding prebiotic autotrophic metabolism in sulfide-rich hydrothermal vent environments. However, geochemical mechanisms to harness the reductive power provided by hydrothermal systems remain to be elucidated. Here, we show that, under a geoelectrochemical condition realizable in the early ocean hydrothermal systems, several metal sulfides (FeS, Ag2S, CuS, and PbS) undergo hour- to day-scale conversion to the corresponding metals at ≤−0.7 V (versus the standard hydrogen electrode). The electrochemically produced FeS-Fe0 assemblage promoted various reactions including certain steps in the reductive tricarboxylic acid cycle with efficiencies far superior to those due to pure FeS. The threshold potential is readily generated in the H2-rich alkaline hydrothermal systems that were probably ubiquitous on the Hadean seafloor. Thus, widespread metal production and metal-sustained primordial metabolism were likely to occur as a natural consequence of the active hydrothermal processes on the Hadean Earth.

scholarly journals Thioester synthesis through geoelectrochemical CO2 fixation on Ni sulfides

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Norio Kitadai ◽  
Ryuhei Nakamura ◽  
Masahiro Yamamoto ◽  
Satoshi Okada ◽  
Wataru Takahagi ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Origin Of Life ◽  
Deep Sea ◽  
Room Temperature ◽  
Nickel Sulfide ◽  
Co2 Fixation ◽  
Hydrothermal Systems ◽  
Standard Hydrogen Electrode ◽  
Hydrogen Electrode ◽  
The Origin Of Life

AbstractA prevailing scenario of the origin of life postulates thioesters as key intermediates in protometabolism, but there is no experimental support for the prebiotic CO2 fixation routes to thioesters. Here we demonstrate that, under a simulated geoelectrochemical condition in primordial ocean hydrothermal systems (–0.6 to –1.0 V versus the standard hydrogen electrode), nickel sulfide (NiS) gradually reduces to Ni0, while accumulating surface-bound carbon monoxide (CO) due to CO2 electroreduction. The resultant partially reduced NiS realizes thioester (S-methyl thioacetate) formation from CO and methanethiol even at room temperature and neutral pH with the yield up to 35% based on CO. This thioester formation is not inhibited, or even improved, by 50:50 coprecipitation of NiS with FeS or CoS (the maximum yields; 27 or 56%, respectively). Such a simple thioester synthesis likely occurred in Hadean deep-sea vent environments, setting a stage for the autotrophic origin of life.

scholarly journals Formation of Thiophene under Simulated Volcanic Hydrothermal Conditions on Earth—Implications for Early Life on Extraterrestrial Planets?

Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 149
Author(s):  
Thomas Geisberger ◽  
Jessica Sobotta ◽  
Wolfgang Eisenreich ◽  
Claudia Huber
Keyword(s):  
Fatty Acids ◽  
Hydrogen Sulfide ◽  
Early Life ◽  
Organic Molecules ◽  
Metal Sulfides ◽  
Early Earth ◽  
Hydrothermal Conditions ◽  
Evolution Of Metabolism ◽  
Thiophene Derivatives ◽  
The Origin Of Life

Thiophene was detected on Mars during the Curiosity mission in 2018. The compound was even suggested as a biomarker due to its possible origin from diagenesis or pyrolysis of biological material. In the laboratory, thiophene can be synthesized at 400 °C by reacting acetylene and hydrogen sulfide on alumina. We here show that thiophene and thiophene derivatives are also formed abiotically from acetylene and transition metal sulfides such as NiS, CoS and FeS under simulated volcanic, hydrothermal conditions on Early Earth. Exactly the same conditions were reported earlier to have yielded a plethora of organic molecules including fatty acids and other components of extant metabolism. It is therefore tempting to suggest that thiophenes from abiotic formation could indicate sites and conditions well-suited for the evolution of metabolism and potentially for the origin-of-life on extraterrestrial planets.

scholarly journals Ideas and perspectives: Development of nascent autotrophic carbon fixation systems in various redox conditions of the fluid degassing on early Earth

2019 ◽  
Vol 16 (8) ◽  
pp. 1817-1828 ◽  
Author(s):  
Sergey A. Marakushev ◽  
Ol'ga V. Belonogova
Keyword(s):  
Carbon Fixation ◽  
Hydrothermal Systems ◽  
System Model ◽  
Early Earth ◽  
Hydrothermal Conditions ◽  
Oxidation Of Methane ◽  
The Earth ◽  
Autotrophic Metabolism ◽  
Metabolic Systems ◽  
Hydrothermal Environments

Abstract. The origin and development of the primary autotrophic metabolism on early Earth were influenced by the two main regimes of degassing of the Earth – reducing (predominance CH4) and oxidative (CO2). Among the existing theories of the autotrophic origin of life in hydrothermal environments, CO2 is usually considered to be the carbon source for nascent autotrophic metabolism. However, the ancestral carbon used in metabolism may have been derived from CH4 if the outflow of magma fluid to the surface of the Earth consisted mainly of methane. In such an environment, the primary autotrophic metabolic systems had to be methanotrophic. Due to the absence of molecular oxygen in the Archean conditions, this metabolism would have been anaerobic; i.e., oxidation of methane must be realized by inorganic high-potential electron acceptors. In light of the primacy and prevalence of CH4-dependent metabolism in hydrothermal systems of the ancient Earth, we propose a model of carbon fixation where the methane is fixed or transformed in a sequence of reactions in an autocatalytic methane–fumarate cycle. Nitrogen oxides are thermodynamically the most favorable among possible oxidants of methane; however, even the activity of oxygen created by mineral buffers of iron in hydrothermal conditions is sufficient for methanotrophic acetogenesis. The hydrothermal system model is considered in the form of a phase diagram, which demonstrates the area of redox and P and T conditions favorable for the development of the primary methanotrophic metabolism.

scholarly journals Impact-Induced Hydrothermal Systems on Early Earth: CH4 Production and the Origin of Life

2020 ◽  
Author(s):  
Kazumu Kaneko ◽  
Yasuhito Sekine ◽  
Takazo Shibuya ◽  
Hisahiro Ueda ◽  
Natsumi Noda
Keyword(s):  
Origin Of Life ◽  
Hydrothermal Systems ◽  
Early Earth ◽  
Ch4 Production ◽  
The Origin Of Life

scholarly journals Kinetics of the ancestral carbon metabolism pathways in deep-branching bacteria and archaea

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Tomonari Sumi ◽  
Kouji Harada
Keyword(s):  
Carbon Metabolism ◽  
Carbon Fixation ◽  
Citrate Synthase ◽  
Tricarboxylic Acid Cycle ◽  
Necessary Condition ◽  
Last Universal Common Ancestor ◽  
Universal Common Ancestor ◽  
Biomass Components ◽  
Kinetics Of ◽  
Reductive Tricarboxylic Acid Cycle

AbstractThe origin of life is believed to be chemoautotrophic, deriving all biomass components from carbon dioxide, and all energy from inorganic redox couples in the environment. The reductive tricarboxylic acid cycle (rTCA) and the Wood–Ljungdahl pathway (WL) have been recognized as the most ancient carbon fixation pathways. The rTCA of the chemolithotrophic Thermosulfidibacter takaii, which was recently demonstrated to take place via an unexpected reverse reaction of citrate synthase, was reproduced using a kinetic network model, and a competition between reductive and oxidative fluxes on rTCA due to an acetyl coenzyme A (ACOA) influx upon acetate uptake was revealed. Avoiding ACOA direct influx into rTCA from WL is, therefore, raised as a kinetically necessary condition to maintain a complete rTCA. This hypothesis was confirmed for deep-branching bacteria and archaea, and explains the kinetic factors governing elementary processes in carbon metabolism evolution from the last universal common ancestor.

scholarly journals A Soluble NADH-Dependent Fumarate Reductase in the Reductive Tricarboxylic Acid Cycle of Hydrogenobacter thermophilus TK-6

2008 ◽  
Vol 190 (21) ◽  
pp. 7170-7177 ◽  
Author(s):  
Akane Miura ◽  
Masafumi Kameya ◽  
Hiroyuki Arai ◽  
Masaharu Ishii ◽  
Yasuo Igarashi
Keyword(s):  
Soluble Fraction ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Fumarate Reductase ◽  
High Sequence Identity ◽  
Catalytic Subunits ◽  
Acid Cycle ◽  
Genes Encoding ◽  
Hydrogenobacter Thermophilus ◽  
Reductive Tricarboxylic Acid Cycle

ABSTRACT Fumarate reductase (FRD) is an enzyme that reduces fumarate to succinate. In many organisms, it is bound to the membrane and uses electron donors such as quinol. In this study, an FRD from a thermophilic chemolithoautotrophic bacterium, Hydrogenobacter thermophilus TK-6, was purified and characterized. FRD activity using NADH as an electron donor was not detected in the membrane fraction but was found in the soluble fraction. The purified enzyme was demonstrated to be a novel type of FRD, consisting of five subunits. One subunit showed high sequence identity to the catalytic subunits of known FRDs. Although the genes of typical FRDs are assembled in a cluster, the five genes encoding the H. thermophilus FRD were distant from each other in the genome. Furthermore, phylogenetic analysis showed that the H. thermophilus FRD was located in a distinct position from those of known soluble FRDs. This is the first report of a soluble NADH-dependent FRD in Bacteria and of the purification of a FRD that operates in the reductive tricarboxylic acid cycle.

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