Chemists at Purdue University have solved a mystery that has stumped scientists for decades by finding a mechanism that explains how peptide-forming processes can take place in water.
Graham Cooks characterized this chemical process as “basically the chemistry behind the beginning of life.” Within the College of Science at Purdue, he teaches analytical chemistry and holds the Henry Bohn Hass Distinguished Professor title. “This is the first proof that elementary molecules, simple amino acids, may spontaneously produce peptides, the building blocks of life, in droplets of pure water. Peptides are the building blocks of all living organisms.” This is a shocking piece of new information.
“In a nutshell, this is the chemistry that led to the first living organisms.” — Graham Cooks
This water-based chemistry, which leads to proteins and, ultimately, to life on Earth, could also lead to a speedier creation of medicines to cure some of the most devastating diseases that affect humankind. The findings of the team were presented in a paper that was published in the journal Proceedings of the National Academy of Sciences.
For many decades, the scientific community has postulated that the oceans were the original home of life on Earth. However, the chemical processes that led to this result remained a mystery. Peptides can be formed by raw amino acids, which were constantly being supplied to the early Earth by meteorites. Peptides can react and latch onto one another. These are the elements that can eventually be assembled into proteins and form life. In a moist, aquatic, or oceanic environment, the procedure involves the strange loss of a water molecule, which appears extremely implausible given the conditions of those environments. Water was necessary for the emergence of life. On the other hand, it required area that was separate from the sea.
Cooks, an authority on mass spectrometry and the chemistry of the early Earth, along with the members of his research team have solved the mystery by discovering the answer to the following riddle: “Water isn’t wet everywhere.” Amino acids that are not produced by living organisms can be converted into the structural components of living things through a series of incredibly rapid chemical reactions that can take place at the water droplet’s boundary with the surrounding air. Therefore, the settings that were most conducive to the development of life were those in which sea spray would fly into the air and waves would pound the land, as well as those in which fresh water would burble down a slope.
“This is the first proof that elementary molecules, simple amino acids, may spontaneously produce peptides, the building blocks of life, in droplets of pure water. Peptides are the building blocks of all living organisms.” This is a shocking piece of new information. — Graham Cooks
Since more than ten years ago, the chemists have been employing mass spectrometers to investigate the chemical processes that take place in droplets that contain water. According to Cooks, the rates of reactions that take place in droplets can be anywhere from a hundred to a million times faster than the reactions that take place when the same chemicals are present in bulk solution.
The rapid rates at which these reactions occur eliminate the need for catalysts, which in turn speeds up the reactions and, in the case of the chemistry of the early Earth, paved the way for the evolution of life. Decades of research in the scientific community have been devoted to trying to figure out how this mechanism operates. If scientists could unlock the mystery of how life first appeared on Earth, it would help them better understand why it occurred and drive their hunt for life elsewhere in the universe, including other planets and even moons.