A new idea connects the synthesis of clays and the origin of metabolism

April 4, 2017, University of Kentucky
Illustration that connects the synthesis of clays and the origin of metabolism. Credit: Ruixin Zhou

The question of how life has begun has fascinated scientists from many disciplines and it was the organic chemist Graham Cairns-Smith who proposed the theory for the origin of life starting from clays instead of polymers such as RNA.

The source of the monomers such as nucleotides, amino acids and dicarboxylic acids were relegated by Cairns-Smith to the evolution of metabolism, which is the of and nucleotides from the citric acid cycle.

This problem of the evolution of metabolism has recently been advanced by the behavior of simple semiconductor minerals such as zinc sulfide (ZnS), which are capable of harvesting sunlight energy and converting this energy into the formation of chemical bonds of dicarboxylic acids from CO2 thus providing the core reactions of universal metabolism before the existence of enzymes.

A connection between ZnS prebiotic photosynthesis and replication has now been established in a paper published by a team of scientists from the University of Kentucky and the Massachusetts Institute of Technology (MIT) in the United Sates, and McGill University in Canada. The paper has related how prebiotic metabolites available from simple sunlight promoted reactions can catalyze the synthesis of (i.e., a zinc clay called sauconite). The work shows that central metabolites such as succinate and malate can enable the nucleation process for clay formation. These prebiotic metabolites have been generated by photocatalysis with ZnS, and this work demonstrates how they can catalyze the synthesis of clays.

The study published in the open access journal Scientific Reports shows how a clay synthesis can proceed catalyzed by prebiotic metabolites in only 20 hours at 90 °C and 1 atm. Clay formation generally requires much longer times as well as higher temperature and pressure. The cryogenic transmission electron microscopy clearly shows that clay nanoparticles can be observed after only 6 hours of synthesis, as verified by the incorporation of aluminum into the tetrahedral layer.

The team noted that the synthesis of clay can proceed at even lower temperatures, i.e., at just 70 °C, with the addition of a single seed particle. The work presents an excellent example of the reproductive power of clay minerals and the mechanism by which prebiotic metabolites catalyze their formation. Clay minerals acting as chemical sponges can retain water and polar organic molecules, and should have played a key role in the origin of life; 1) protecting against ultraviolet radiation, and 2) concentrating and catalyzing the polymerization of organic molecules such as RNA. The outcome of this work has direct implications to understand the origin of life on the early Earth and other rocky planets.

Explore further: Sun's UV light helped spark life

More information: More information: Ruixin Zhou, Kaustuv Basu, Hyman Hartman, Christopher J. Matocha, S. Kelly Sears, Hojatollah Vali & Marcelo I. Guzman. Catalyzed Synthesis of Zinc Clays by Prebiotic Central Metabolites, Scientific Reports, 7, 522, 2017. DOI: 10.1038/s41598-017-00558-1

Related Stories

Sun's UV light helped spark life

March 31, 2017

High energy, ultraviolet radiation from the Sun is a known to hazard to life, yet the energy provided by our star has played an important role as the essential driver of life on Earth.

How did phosphate get into RNA?

August 18, 2016

The phosphate ion is almost insoluble and is one of the most inactive of Earth's most abundant phosphate minerals. So how could phosphate have originally been incorporated into ribonucleotides, the building blocks of RNA, ...

Turning glass into clay

July 6, 2012

The magic mineral and microbial processes that transform volcanic glass into clay have been identified, adding important knowledge to how clay is formed.

Martian clay minerals might have a much hotter origin

September 12, 2012

(Phys.org)—Ancient Mars, like Earth today, was a diverse planet shaped by many different geologic processes. So when scientists, using rovers or orbiting spacecraft, detect a particular mineral there, they must often consider ...

Did clay mould life's origins?

April 4, 2011

(PhysOrg.com) -- An Oxford University scientist has taken our understanding of the origin of life a step further.

Recommended for you

New theory shows how strain makes for better catalysts

April 20, 2018

Brown University researchers have developed a new theory to explain why stretching or compressing metal catalysts can make them perform better. The theory, described in the journal Nature Catalysis, could open new design ...

Machine-learning software predicts behavior of bacteria

April 19, 2018

In a first for machine-learning algorithms, a new piece of software developed at Caltech can predict behavior of bacteria by reading the content of a gene. The breakthrough could have significant implications for our understanding ...

Spider silk key to new bone-fixing composite

April 19, 2018

UConn researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

GLUT5 fluorescent probe fingerprints cancer cells

April 19, 2018

Determining the presence of cancer, as well as its type and malignancy, is a stressful process for patients that can take up to two weeks to get a diagnosis. With a new bit of technology—a sugar-transporting biosensor—researchers ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.