How RNA formed at the origins of life

May 19, 2017
This is a computer graphic of an RNA molecule. Credit: Richard Feldmann/Wikipedia

A single process for how a group of molecules called nucleotides were made on the early Earth, before life began, has been suggested by a UCL-led team of researchers.

Nucleotides are essential to all on Earth as they form the building blocks of DNA or RNA, and understanding how they were first made is a long-standing challenge that must be resolved to elucidate the origins of life.

In a study, published today in Nature Communications and funded by the Engineering and Physical Sciences Research Council, the Simons Foundation and the Origins of Life Challenge, researchers from UCL, Harvard University and Massachusetts General Hospital suggest a single chemical mechanism by which both classes of nucleotides—purines and pyrimidines—could have formed together.

Before now, scientists thought that the two classes of must have been made separately and under mutually incompatible conditions. This study is the first to show that both purines and pyrimidines can be formed from a common precursor molecule that existed before life began.

"We provide a new perspective on how the original RNA molecules were made and suggest a simple chemical solution for delivering both purine and nucleotides at the origins of life," explained corresponding author, Dr Matthew Powner (UCL Chemistry).

"RNA is the corner stone of all life on Earth and probably carried the first information at the outset of life, but making RNA requires both purine and pyrimidine nucleotides to be simultaneously available. A solution to this problem has remained elusive for more than 50 years."

The team demonstrated how purines and pyrimidine nucleotides can both be assembled on the same sugar scaffold to form molecules called ribonucleotides which are used to construct RNA.

Purine and pyrimidine nucleotides are used to create the DNA and RNA. The purine and pyrimidine nucleotides bind to one another through specific molecular interactions that provide a mechanism to copy and transfer information at the molecular level, which is essential for genetics, replication and evolution. Therefore understanding the origins of nucleotides is thought to be key to understanding the origins of life itself.

The team discovered that , called 8-oxo-adenosine and 8-oxo-inosine, which are purine ribonucleotides, can be formed under the same chemical conditions as the natural pyrimidine ribonucleotides. They also found that one chemical precursor can divergently yield both purine and pyrimidine ribonucleotides.

"The mechanism we've reported gives both classes of molecule the same stereochemistry that is universally found in the sugar scaffold of biological nucleic acids, suggesting that 8-oxo-purine ribonucleotides may have played a key role in primordial nucleic acids," said Dr Shaun Stairs (UCL Chemistry), first author of the study.

The team now plans to further investigate mechanisms that use 8-oxo-purines to transfer information, which could help scientists better understand life's first informational transfer systems.

Explore further: Chemists offer more evidence of RNA as the origin of life

More information: 'Divergent prebiotic synthesis of pyrimidine and 8-oxo-purine ribonucleotides', Nature Communications (2017). DOI: 10.1038/NCOMMS15270

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12 comments

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zave
5 / 5 (2) May 19, 2017
I can't wait until they make life with this.I want more proof.
Whydening Gyre
4.4 / 5 (7) May 19, 2017
Well, it took naature quite a while to work it out.
We might not be any faster...:-)
zave
5 / 5 (2) May 19, 2017
I am holding out hope for them to speed up the process or make from what they have discovered a bacteria.Bacteria can be pretty small.
Whydening Gyre
3.8 / 5 (4) May 19, 2017
I am holding out hope for them to speed up the process or make from what they have discovered a bacteria.Bacteria can be pretty small.

A simple virus would be even "smaller"...:-)
(And less complex)
ddaye
5 / 5 (1) May 19, 2017
Well, it took naature quite a while to work it out.
We might not be any faster...:-)

We could be --we cheat.
dusty55art
1.7 / 5 (6) May 20, 2017
So they think that's how God did it? I thought that he established the information in a program within the infinite structure that was the seed of the universe. Could this be the same thing?
infinitestructure.com
Whydening Gyre
2.3 / 5 (3) May 20, 2017
So they think that's how God did it?

I think that's how "(G)eodesically (O)rdinated (D)ata" does it....
humy
3.8 / 5 (4) May 21, 2017
this link makes a big illogical assumption. It assumes that the first life must have had the nucleotides purines and pyrimidines therefore those nucleotides must have formed BEFORE the first life. Why couldn't the first life had an RNA-like molecules (and not DNA because DNA probably evolved later) that had a DIFFERENT set of nucleotides (a set of nucleotides that doesn't exist in modern life) which did NOT including purines and pyrimidines? And, only later, AFTER the first life formed, life evolved purines and pyrimidines into their RNA-like molecules ? Why assume that to be any less probable let alone impossible!?
zave
5 / 5 (2) May 21, 2017
That is a good idea you have.I like it.
johnultrawild
not rated yet May 22, 2017
@humy, science can only describe/explain that which can be known, if something doesn't exist and cannot be found to have existed ie non-purine and non-pyrimidine nucleotide RNA, then the idea is pure conjecture, then again you may argue that they haven't looked for anything else. Science works with the evidence it has at hand, if new evidence arrives then that is also taken into account. But this is just another chicken and egg thing, regardless of the components, there has yet to be found a repeatable mechanism for the construction of RNA.
Bart_A
1 / 5 (4) May 22, 2017
You can't just have these molecules. They need to have structure and order, they need information, they need useful functions. And they need to be able to replicate. As so on and so forth. And there are actually scientists that still think this can happen by chance??
EnsignFlandry
5 / 5 (2) May 22, 2017
You can't just have these molecules. They need to have structure and order, they need information, they need useful functions. And they need to be able to replicate. As so on and so forth. And there are actually scientists that still think this can happen by chance??


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