Scientists have recently done experiments in a lab to figure out how life first started on Earth, and they found out that ancient proteins had to mix with certain kinds of acids to make all kinds of living things, including humans, animals and plants.
This new research helped us understand better the age-old mystery behind the beginnings of life on our planet.
Research led by chemists at Johns Hopkins and Charles University in the Czech Republic has discovered that all living things on Earth, from bacteria to humans, have something in common: the same amino acids. This means all things are connected through a single ancestor—the so-called tree of life—who had these precious building blocks for life. The research is discovering why this ancient being got these miraculous ingredients.
The scientists just released the results of their study in a magazine called Journal of the American Chemical Society. To prove how proteins were first made billions of years ago, they ran tests using amino acids that were common way before life began on Earth.
Scientists discovered that long ago, some of the amino acids around could help proteins to form specific shapes in order to do particular jobs. This means that life was able to thrive on Earth because not only were there amino acids available but they also had abilities that meant they could be used well.
“Protein folding was a way for us to have evolution happen before life even existed on Earth,” said Fried. “This means that natural selection – something that helps new things be created in life – could have occurred without DNA being involved!”
Our Earth had hundreds of different amino acids in the past, but right now, all living things only use 20 out of these compounds. People call them “canonical” acids. Scientists have been trying to understand why these 20 compounds are so special.
Earth was about a billion years old when its air contained different gases such as ammonia and carbon dioxide that combined with the strong ultraviolet rays from the Sun to form some basic amino acids. Other amino acids were carried here from space by meteorites, and this mixture of ingredients helped life on Earth make whatever it needed out of 10 elementary amino acids.
Fried’s team is doing new research to try and answer the question of how all the other things came to be – not just the “modern” kinds of amino acids. They want to know why certain amino acids were chosen over others.
Scientists think Earth is really old; about 4.6 billion years old. It wasn’t until 3.8 billion years ago that DNA, proteins and other molecules started becoming simple living organisms. This new research can help to figure out what happened during the time between these two timespans.
Fried said that to have evolution, like Charles Darwin talked about, you need certain molecules like DNA and RNA that turn into proteins. But, if the DNA needs proteins to be made, then it’s kind of like a chicken-and-egg situation – which comes first? Research suggests that natural selection might have chosen some building blocks even before Charles Darwin’s idea of evolution.
Scientists have discovered amino acids in asteroids far away from Earth. This means that these compounds are everywhere else in space as well. Fried also thinks this could help us to find out whether there is life outside of our planet. She said, “Amino acids seem to be present all around the universe. So if we happen to discover any living things outside of Earth, they might not differ much.”
Scientists wrote an article that was published in the “Journal of the American Chemical Society” on February 24,2023. They suggested that some natural physical limits picked what types of amino acids could be part of life when it first started.
Reference: “Early Selection of the Amino Acid Alphabet Was Adaptively Shaped by Biophysical Constraints of Foldability” by Mikhail Makarov, Alma C. Sanchez Rocha, Robin Krystufek, Ivan Cherepashuk, Volha Dzmitruk, Tatsiana Charnavets, Anneliese M. Faustino, Michal Lebl, Kosuke Fujishima, Stephen D. Fried and Klara Hlouchova, 24 February 2023, Journal of the American Chemical Society.
DOI: 10.1021/jacs.2c12987
This study was sponsored by the Human Frontier Science Program and the NIH Director’s New Innovator Award.
