A Simple Spark That Might Clarify How Life Started

Scientists have recreated an important step that will have set life in movement practically 4 billion years in the past.

By displaying how amino acids, the building blocks of proteins, could spontaneously link with RNA under early Earth conditions, researchers have revealed a potential missing link in biology’s origins.

Origins of Life’s Building Blocks

Researchers at UCL have discovered how two essential ingredients of life, RNA (ribonucleic acid) and amino acids, may have naturally combined about four billion years ago at the dawn of life.

Amino acids are the basic components of proteins, which act as the engines of life and drive nearly every biological function. However, proteins cannot copy themselves or generate instructions for their own production. Those instructions come from RNA, a molecule closely related to DNA (deoxyribonucleic acid).

Proteins, RNA, and the Blueprint of Life

In findings published in Nature, the team successfully attached amino acids to RNA under conditions similar to those that might have existed on early Earth. Scientists have been attempting to accomplish this since the early 1970s without success until now.

Professor Matthew Powner, senior author from UCL’s Department of Chemistry, explained: “Life relies on the ability to synthesize proteins – they are life’s key functional molecules. Understanding the origin of protein synthesis is fundamental to understanding where life came from.

“Our study is a big step towards this goal, showing how RNA might have first come to control protein synthesis.

Toward Understanding Protein Synthesis

“Life today uses an immensely complex molecular machine, the ribosome, to synthesize proteins. This machine requires chemical instructions written in messenger RNA, which carries a gene’s sequence from a cell’s DNA to the ribosome. The ribosome then, like a factory assembly line, reads this RNA and links together amino acids, one by one, to create a protein.

“We have achieved the first part of that complex process, using very simple chemistry in water at neutral pH to link amino acids to RNA. The chemistry is spontaneous, selective, and could have occurred on the early Earth.”

Simple Chemistry with Big Implications

Previous attempts to attach amino acids to RNA used highly reactive molecules, but these broke down in water and caused the amino acids to react with each other, rather than become linked to RNA.

For the new study, the researchers took inspiration from biology, using a gentler method to convert life’s amino acids into a reactive form. This activation involved a thioester, a high-energy chemical compound important in many of life’s biochemical processes and that has already been theorized to play a role at the start of life.^[1]

Professor Powner stated: “Our study unites two prominent origin of life theories – the ‘RNA world’, where self-replicating RNA is proposed to be fundamental, and the ‘thioester world’, in which thioesters are seen as the energy source for the earliest forms of life.”

Bridging Competing Origin Theories

To type these thioesters, the amino acids react with a sulfur-bearing compound known as pantetheine. Last yr, the identical workforce printed a paper demonstrating that pantetheine may be synthesized underneath early Earth-like circumstances, suggesting it was prone to play a task within the origin of life.

The subsequent step, the researchers stated, was to find out how RNA sequences might bind preferentially to particular amino acids, permitting RNA to start coding directions for protein synthesis—the origin of the genetic code.

“There are numerous problems to overcome before we can fully elucidate the origin of life, but the most challenging and exciting remains the origins of protein synthesis,” stated Professor Powner.

Lead writer Dr. Jyoti Singh, from UCL Chemistry, stated: “Imagine the day that chemists may take easy, small molecules, consisting of carbon, nitrogen, hydrogen, oxygen, and sulfur atoms, and from these LEGO items type molecules able to self-replication. This can be a monumental step in the direction of fixing the query of life’s origin.

“Our research brings us nearer to that objective by demonstrating how two primordial chemical LEGO items (activated amino acids and RNA) might have constructed peptides,^[2] brief chains of amino acids which can be important to life.

“What is particularly groundbreaking is that the activated amino acid used in this study is a thioester, a type of molecule made from Coenzyme A, a chemical found in all living cells. This discovery could potentially link metabolism, the genetic code, and protein building.”

While the paper focuses solely on the chemistry, the analysis workforce stated that the reactions they demonstrated might plausibly have taken place in swimming pools or lakes of water on the early Earth (however unlikely within the oceans, because the concentrations of the chemical compounds would doubtless be too diluted).

The reactions are too small to see with a visible-light microscope and had been tracked utilizing a variety of strategies which can be used to probe the construction of molecules, together with a number of sorts of magnetic resonance imaging (which exhibits how the atoms are organized) and mass spectrometry (which exhibits the scale of molecules).

Notes

1. The Nobel laureate Christian de Duve proposed that life started with a “thioester world” – a metabolism-first principle that envisages life was began by chemical reactions powered by the vitality in thioesters.
2. Peptides sometimes include two to 50 amino acids, whereas proteins are bigger, usually containing lots of and even 1000’s of amino acids, and are folded right into a 3D form. As a part of their research, the analysis workforce confirmed how, as soon as the amino acids had been loaded onto the RNA, they might be synthesized with different amino acids to type peptides.

Reference: “Thioester-mediated RNA aminoacylation and peptidyl-RNA synthesis in water” by Jyoti Singh, Benjamin Thoma, Daniel Whitaker, Max Satterly Webley, Yuan Yao and Matthew W. Powner, 27 August 2025, Nature.
DOI: 10.1038/s41586-025-09388-y

The work was funded by the Engineering and Physical Sciences Research Council (EPSRC), the Simons Foundation and the Royal Society.

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