Scientists find potential 'missing link' in chemistry that led to life on Earth

November 6, 2017
Credit: CC0 Public Domain

Chemists at The Scripps Research Institute (TSRI) have found a compound that may have been a crucial factor in the origins of life on Earth.

Origins-of-life researchers have hypothesized that a chemical reaction called phosphorylation may have been crucial for the assembly of three key ingredients in early : short strands of nucleotides to store genetic information, short chains of amino acids (peptides) to do the main work of cells, and lipids to form encapsulating structures such as cell walls. Yet, no one has ever found a phosphorylating agent that was plausibly present on early Earth and could have produced these three classes of molecules side-by-side under the same realistic conditions.

TSRI chemists have now identified just such a compound: diamidophosphate (DAP).

"We suggest a phosphorylation chemistry that could have given rise, all in the same place, to oligonucleotides, oligopeptides, and the cell-like structures to enclose them," said study senior author Ramanarayanan Krishnamurthy, associate professor of chemistry at TSRI. "That in turn would have allowed other chemistries that were not possible before, potentially leading to the first simple, cell-based living entities."

The study, reported today in Nature Chemistry, is part of an ongoing effort by scientists around the world to find plausible routes for the epic journey from pre-biological chemistry to cell-based biochemistry.

Other researchers have described chemical reactions that might have enabled the phosphorylation of pre-biological molecules on the early Earth. But these scenarios have involved different phosphorylating agents for different types of molecule, as well as different and often uncommon reaction environments.

"It has been hard to imagine how these very different processes could have combined in the same place to yield the first primitive life forms," said Krishnamurthy.

He and his team, including co-first authors Clémentine Gibard, Subhendu Bhowmik, and Megha Karki, all postdoctoral research associates at TSRI, showed first that DAP could phosphorylate each of the four nucleoside of RNA in water or a paste-like state under a wide range of temperatures and other conditions.

With the addition of the catalyst imidazole, a simple organic compound that was itself plausibly present on the early Earth, DAP's activity also led to the appearance of short, RNA-like chains of these phosphorylated building blocks.

Moreover, DAP with water and imidazole efficiently phosphorylated the lipid building blocks glycerol and fatty acids, leading to the self-assembly of small phospho-lipid capsules called vesicles—primitive versions of cells.

DAP in water at room temperature also phosphorylated the glycine, aspartic acid and glutamic acid, and then helped link these molecules into short peptide chains (peptides are smaller versions of proteins).

"With DAP and water and these mild conditions, you can get these three important classes of pre-biological molecules to come together and be transformed, creating the opportunity for them to interact together," Krishnamurthy said.

Krishnamurthy and his colleagues have shown previously that DAP can efficiently phosphorylate a variety of simple sugars and thus help construct phosphorus-containing carbohydrates that would have been involved in early life forms. Their new work suggests that DAP could have had a much more central role in the origins of life.

"It reminds me of the Fairy Godmother in Cinderella, who waves a wand and 'poof,' 'poof,' 'poof,' everything simple is transformed into something more complex and interesting," Krishnamurthy said.

DAP's importance in kick-starting life on Earth could be hard to prove several billion years after the fact. Krishnamurthy noted, though, that key aspects of the molecule's chemistry are still found in modern biology.

"DAP phosphorylates via the same phosphorus-nitrogen bond breakage and under the same conditions as protein kinases, which are ubiquitous in present-day life forms," he said. "DAP's phosphorylation chemistry also closely resembles what is seen in the reactions at the heart of every cell's metabolic cycle."

Krishnamurthy now plans to follow these leads, and he has also teamed with early-Earth geochemists to try to identify potential sources of DAP, or similarly acting phosphorus-nitrogen compounds, that were on the planet before life arose.

"There may have been minerals on the early Earth that released such phosphorus-nitrogen compounds under the right conditions," he said. "Astronomers have found evidence for phosphorus-nitrogen compounds in the gas and dust of interstellar space, so it's certainly plausible that such compounds were present on the early Earth and played a role in the emergence of the complex molecules of ."

Explore further: Could interstellar ice provide the answer to birth of DNA?

More information: Phosphorylation, oligomerization and self-assembly in water under potential prebiotic conditions, Nature Chemistry (2017). nature.com/articles/doi:10.1038/nchem.2878

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Going
3.9 / 5 (9) Nov 06, 2017
One day we will be regularly putting inorganic chemicals into sterile bottles and getting something like Life to self assemble. Then the miracle seekers will have to go elsewhere.
Bart_A
1.3 / 5 (15) Nov 06, 2017
"It reminds me of the Fairy Godmother in Cinderella, who waves a wand and 'poof,' 'poof,' 'poof,' everything simple is transformed into something more complex and interesting," Krishnamurthy said.


Exactly! Evolution, and the belief that life came from non-life, is really a fairytale. There are way too many "missing links" that no one will ever find. Not only do many, many molecules need to come together all at the same time, but they have to have real information in them, and be able to replicate, etc.

Sorry, Going, but there will never be Life to self assemble.

Mark Thomas
5 / 5 (4) Nov 06, 2017
If God is God because He alone was able to create life, what does it mean if we can create life too? I understand Craig Venter and company constructed a living cell from wholly man-made DNA way back in 2010. So if we manage to create more useful creatures than exist in nature does that mean we will have surpassed God in that regard?
retrosurf
5 / 5 (1) Nov 06, 2017
Mark, your question presumes that a life can be evaluated in some form based on utility ("more useful creatures"). Utility, as a philosophical concept, requires a being or entity for whom the utility of the lifeform is evaluated.

We cannot know the utility that lifeforms have for God. We cannot know if a salmon makes God happier than a jumping spider. We cannot know how happy God is about an organism that we created. We cannot know if a lifeform has more utility for us than it does for God.

The final issue, and most damning, is our uncertainty if we are actually talking about an empty set when we talk about God. Assertions about an empty set have no truth value (they are neither true nor false).
Mark Thomas
not rated yet Nov 06, 2017
"your question presumes that a life can be evaluated in some form based on utility"

You can't answer that question so you are trying to dodge it by nit-picking. But essence of the question remains. If people create lifeforms more useful to us in any aspect than natural ones, will we have surpassed God in that respect?

Here's another one, if God created Earth then God cannot be from Earth. Would you agree God must be an alien by definition?
retrosurf
5 / 5 (1) Nov 06, 2017
If you are making assertions about God, I probably can't agree with them; so no, I cannot agree that God must be an alien. I can't say if we've surpassed God in any fashion.

That's what the third paragraph is about.

Bye-bye, Mark.
Mark Thomas
5 / 5 (3) Nov 06, 2017
Genesis 1:1-3 "In the beginning, God created the heavens and the earth. The Earth was without form and void, and darkness was over the face of the deep. And the Spirit of God was hovering over the face of the waters. And God said, "Let there be light," and there was light."

You may be getting a bad case of cognitive dissonance right now. Your head is telling you the logic is correct, but your gut won't let you admit it.

Here is the logic:
1. The Bible says God created the Earth.
2. If God created Earth, God must have existed at least momentarily before the creation of the Earth. Other scripture implies God is eternal and infinitely old, e.g., Psalm 90:2.
3. If God existed prior to the creation of the Earth, God cannot be from Earth.
4. If God is not from Earth, God must be an alien.
jonesdave
5 / 5 (5) Nov 06, 2017
Or so called 'intelligent design.' Nobody can actually tell us who this designer was. He just got magicked into existence. That is why the court in the Dover High School case ruled that it was essentially b*llocks.
And had nothing to do with science. Hey ho.
omegatalon
3.5 / 5 (2) Nov 06, 2017
Potential means nothing is written in stone and this is just the latest idea of what might have happened because the planet was bombarded with comets for billions of years and something could have tagged a ride.
jonesdave
5 / 5 (3) Nov 06, 2017
Potential means nothing is written in stone and this is just the latest idea of what might have happened because the planet was bombarded with comets for billions of years and something could have tagged a ride.


There are all sorts of reasons why life may have started. I'll give you that. We know more about comets now than we did a few years ago. The trip to Bennu will tell us more about asteroids. ID and creationism are just crap, though.
yep
1 / 5 (2) Nov 07, 2017
Big Bang was magicked into existence, it was essentially b*llocks.
And had nothing to do with science.
Ha fixed it for you!

So Bart your problem is your faith is in a recently founded religion sponsored by the Roman state for social control. Your ego is tied up in the idea your cousin is pond scum. Get over it and read more then one book. It might expand the worth of your life to know there are other ways to be.
Whydening Gyre
5 / 5 (4) Nov 07, 2017
Genesis 1:1-3 "In the beginning, God created the heavens and the earth. The Earth was without form and void, and darkness was over the face of the deep. And the Spirit of God was hovering over the face of the waters. And God said, "Let there be light," and there was light."

It's cognitively dissident not to ask what the water was floating on in the first place...

Here is the logic:
1. The Bible says God created the Earth.
2. If God created Earth, God must have existed at least momentarily before the creation of the Earth. Other scripture implies God is eternal and infinitely old, e.g., Psalm 90:2.
3. If God existed prior to the creation of the Earth, God cannot be from Earth.
4. If God is not from Earth, God must be an alien.

Here is my logic - a god could be a cloud of cooling chemicals, cuz it was hovering over the water.
(Or a pelican crapping...)
Parsec
5 / 5 (5) Nov 07, 2017
Attempting to answer origin of life questions by invoking supernatural forces to deny that those questions exist doesn't work. For one thing, if God created everything, who or what created God? Any answer you can supply to the origin of God's existence can apply to the origin of life itself.

I have never understood why people who claim God created everything are so darn sure that he didn't manifest that creation using the principles of physics, chemistry and biology. Such incredible hubris is uniquely human.
TheGhostofOtto1923
5 / 5 (1) Nov 07, 2017
your question presumes that a life can be evaluated in some form based on utility ("more useful creatures"). Utility, as a philosophical concept
'Utility' is not a philo concept. Function is a scientific one.
requires a being or entity for whom the utility of the lifeform is evaluated
Well even if this were true it would not be YOUR god, the god of abraham. That god wrote a book in which he claimed to be perfect, and yet wrote about people whom we know never existed and events that never happened.

Theism is not deism although both are philo/religio nonsense and deception.

Perfect gods have no need of artistic licence.
We cannot know the utility that lifeforms have for God
Science tells us with increasing confidence that function is entirely knowable.

We learn more every day and as a result the bookgods look less credible every day.
TheGhostofOtto1923
5 / 5 (3) Nov 07, 2017
Exactly!... the belief that life came from non-life, is really a fairytale.
"7 Then the Lord God formed a man from the dust of the ground and breathed into his nostrils the breath of life, and the man became a living being." Gen2

-Exactly! A fairytale.
rogerdallas
5 / 5 (2) Nov 08, 2017
If I got lost in the wilderness I would want a Bible handy, so I could tear out the pages and use them for toilet paper. Otherwise, no.
Whydening Gyre
5 / 5 (1) Nov 08, 2017
Exactly!... the belief that life came from non-life, is really a fairytale.
"7 Then the Lord God formed a man from the dust of the ground and breathed into his nostrils the breath of life, and the man became a living being." Gen2

-Exactly! A fairytale.

Except there's no cute, little anthropomorphic critters or princesses...

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