Chemists at Purdue University in the US have discovered a mechanism by which peptide-forming reactions take place in water – something that has puzzled scientists for decades.

“This is essentially the chemistry behind the origin of life,” said Graham Cooks, professor of analytical chemistry in Purdue’s College of Science. “This is the first demonstration that primordial molecules, simple amino acids, spontaneously form peptides, the building blocks of life, in drops of pure water. This is a dramatic discovery.”

This water-based chemistry, which leads to proteins and thus life on Earth, could also lead to faster development of drugs to treat many of humanity’s diseases.

The team’s finding was published in the journal Proceedings of the National Academy of Sciences.

A dilemma that has puzzled scientists for decades

For decades, scientists have theorized that life on Earth began in the oceans. However, the chemistry remained an enigma. Amino acids can react and bond with each other to form peptides, the building blocks of proteins and ultimately life.

Oddly, the process requires the loss of a water molecule, which seems highly unlikely in a moist, aqueous, or oceanic environment. In order for life to form, it needed water.

Cooks, an expert in mass spectrometry and early Earth chemistry, and his team discovered the answer to this conundrum. “Water is not wet everywhere.” At the edges, where the water drop meets the atmosphere, incredibly fast reactions can occur, turning abiotic amino acids into the building blocks of life, he writes EurekAlert.

Chemists have spent more than 10 years using mass spectrometers to study chemical reactions in droplets containing water.

Clues to extraterrestrial life

“Reaction rates in the droplets are a hundred to a million times faster than the reactions of the same chemicals reacting in solution,” Cooks said.

The rates of these reactions render catalysts useless, speeding up reactions and, in the case of early Earth chemistry, making possible the evolution of life. Understanding how this process works has been the focus of decades of scientific research.

The secret of how life arose on Earth can help scientists understand why it did and inform the search for life on other planets or even the moons.

Understanding how amino acids built themselves into proteins and ultimately life forms is revolutionizing scientists’ understanding of chemical synthesis.

That same chemistry could now help chemists speed up reactions essential to the discovery and development of new drugs and therapeutic treatments for disease.

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