WEST LAFAYETTE, Ind. — Life on Earth may have begun with a chemical “Big Bang” — in a drop of water, according to new research. Researchers at Purdue University say this event in early Earth chemistry provided reactions up to a million times quicker than normal, kick-starting evolution.
The discovery has a host of implications, from speeding up the development of drugs to finding alien life on other worlds.
“This is essentially the chemistry behind the origin of life,” says Graham Cooks, the Henry Bohn Hass Distinguished Professor of Analytical Chemistry in Purdue’s College of Science, in a media release. “This is the first demonstration that primordial molecules, simple amino acids, spontaneously form peptides, the building blocks of life, in droplets of pure water. This is a dramatic discovery.”
The water-based chemistry led to proteins and life forming on Earth. It may hold the key to better medications for humanity’s most debilitating diseases, the researchers suggest. The radical theory suggests life happened all at once, in a chemical explosion. It has long been thought the ingredients came together slowly, bit by bit.
“The rates of reactions in droplets are anywhere from a hundred to a million times faster than the same chemicals reacting in bulk solution,” Cooks says.
Speeding up these reactions makes catalysts unnecessary. Understanding how this process works would be the “holy grail” of chemistry. The new findings shed light on why life developed on Earth and informs the search for it on other planets or moons.
For decades, scientists have theorized that life began in the oceans, but the chemistry remained an enigma. When Earth formed 4.5 billion years ago, it was a sterile ball of rock, slammed by meteorites and covered with erupting volcanoes.
Within a billion years, it became inhabited by microorganisms. Today, life covers every inch of the planet, from the highest mountains to the deepest seas. However, every other world in the solar system seems lifeless. What happened for barren rocks, sands, and chemicals to give rise to life has stumped the greatest minds.
Raw amino acids – something meteorites deliver from the cosmos – can react and latch together to form peptides. Puzzlingly, these building blocks of proteins and life also require the loss of a water molecule. It’s highly unlikely in a wet, aqueous, or oceanic environment. For life to form, water was necessary, but it also needed space away from the water.
Prof. Cooks, an expert in early Earth chemistry, and his colleagues have now uncovered the answer to the riddle. They’ve spent over 10 years using mass spectrometer scanners to analyze chemical reactions in droplets containing water.
“Water isn’t wet everywhere,” Prof. Cooks explains.
On the margins, where a droplet meets the atmosphere, incredibly rapid reactions can take place, transforming abiotic amino acids into the building blocks of life. Places where sea spray flies into the air and waves pound the land, or where fresh water burbles down a slope, were fertile landscapes for life’s potential evolution.
Understanding how amino acids built themselves up into proteins and, eventually, life-forms could revolutionize chemical synthesis. Quicker reactions are critical to discovering and developing new drugs and therapeutic treatments for life-threatening illnesses.
“If you walk through an academic campus at night, the buildings with the lights on are where synthetic chemists are working,” Cooks concludes. “Their experiments are so slow that they run for days or weeks at a time. This isn’t necessary, and using droplet chemistry, we have built an apparatus, which is being used at Purdue now, to speed up the synthesis of novel chemicals and potential new drugs.”
The study is published in Proceedings of the National Academy of Sciences.
South West News Service writer Mark Waghorn contributed to this report.