Chemistry Behind the Origin of Life: Researchers Uncovered the Mechanism for Peptide-Forming Reactions in Water

Chemists from Purdue University have uncovered the chemistry behind the origin of life. Professor Graham Cooks said this is the first demonstration that primordial molecules, simple amino acids, form peptides in water droplets.

According to Phys.org, it has long been theorized that life on Earth began in the ocean, but the chemistry behind it remained unknown until now, wherein researchers discovered the mechanism for peptide-forming reactions in water that led to the birth of the building blocks of life. The findings could lead to faster development of drugs to treat debilitating diseases.

(Photo: Pixabay/MartinStr)
Chemistry Behind the Origin of Life: Researchers Uncovered the Mechanism for Peptide-Forming Reactions in Water

Life Begins in Water

The earliest evidence of life is cyanobacteria found in rocks in Australia that lived 3.5 billion years ago. They were a primitive group of organisms that would have relied on the Sun to produce energy, and at that time, methane was abundant when oxygen was not yet present.

According to ZME Science, these were considered complex lifeforms, so scientists thought that the origins of life could have started earlier, although nobody knows exactly how early. But they are now beginning to understand how life appeared in the first place.

Evidence suggests that Earth harbored liquid water oceans as early as 4.3 billion years ago, or only about 250 million years after it formed and nearly 800 million years before microfossils of bacteria emerged.

Paradoxically, too much water is not essential to life as it does not allow raw amino acids to react and link into peptides, essential elements for life on Earth. For peptides to form, water molecule needs to disintegrate, which is hard to do in a world of ocean.

Nevertheless, life emerged, so scientists are looking for this missing puzzle piece to fill in the blanks and understand the origins of life on Earth. It is something that researchers at Purdue University, led by Professor Cooks, an expert in mass spectrometry and early Earth chemistry, have sought to find out for decades.

Water Isn't Wet Everywhere

The chemistry as to how life on Earth began in the oceans remained an enigma for decades. Phys.org reports that raw amino acids from meteorites that fell into Earth can react and latch together to form peptides, which are the building blocks of proteins and life. Cooks and his team may have uncovered the answer to the riddle: "Water isn't wet everywhere."

In their study, titled "Aqueous Microdroplets Enable Abiotic Synthesis and Chain Extension of Unique Peptide Isomers From Free Amino Acids," published in PNAS, they explained that incredible rapid reactions could take place where the water droplet meets the atmosphere. These reactions transform abiotic amino acids into the building blocks of life.

More so, fertile landscapes for life's potential evolution are those places where sea spray flies into the air and waves pound the land or freshwater flows down a slope. The team has spent over a decade using mass spectrometers to understand the chemical reactions in water droplets.

Cook said that the rate of reactions in these droplets is so fast that they could be a hundred or a million times faster than the chemical reactions in bulk solution. The fast rate makes the catalyst useless as it speeds up the reaction and makes the evolution of life possible. Understanding how this works has been the goal of uncovering the origins of life on Earth and informing the search for life on other planets or moons.

Furthermore, understanding the process by which amino acids built themselves into proteins and, eventually, life forms revolutionizes the understanding of chemical synthesis to help synthetic chemists speed reactions crucial in discovering and developing new drugs and treatments for diseases.