by NASA
A team of researchers has simulated Earth’s conditions in the early part of its history, about 4.6 billion years ago, seeking a better understanding of how amino acids created the first ingredients for life.
Together, amino acids form proteins that play vital roles in organisms. This new study is designed to help determine why a particular group 20 “normal” amino acids it is used on a repetitive basis to make proteins when there are so many.
It is believed that these 20 amino acids are made up of 10 collected from the atmosphere, as well as meteorite fragments from the early Earth, along with another 10 added in a second phase. However, the selection process for the latter is unclear, she said Science Alert.
“We see the same amino acids in all organisms, from humans to bacteria, and that’s because everything on Earth is connected through this tree of life that has one origin, one organism that was the ancestor of all living things,” said chemist Stephen Fried, from Johns Hopkins University, in the US.
“We describe the events that shaped why this ancestor got the amino acids it got,” continued the scientist, one of the authors of the study recently published in Journal of the American Chemical Society.
Through a reconstruction of primary protein synthesis, the researchers showed that ancient organic compounds would have better favored amino acids during protein cross-linking, tailoring them for specific functions.
In other words, a process of evolution or natural selection was taking place even at this stage: not the amino acids that were readily available were harvested, but those best suited to a particular role.
If other amino acids had been selected as part of the core group billions of years ago, scientists have determined that the building blocks of life themselves would not have been as effective.
“Protein crossover basically allowed us to evolve before there was life on our planet,” said Stephen Fried. “You could have evolution before you had biology, you could have natural selection on the chemicals that are useful for life, even before there was DNA,” he said.
Molecules, including proteins, are believed to have begun to compose simple organisms 3.8 billion yearsso there is a piece of Earth’s past history that scientists have been very interested in investigating.
The team suggests that the “backwards” 10 amino acids were specifically chosen for their abilities to cross-link proteins, allowing DNA to be copied and the proteins that sparked life to be produced.
This research can teach us more about the possibilities of microorganisms on other planets and our own: the same amino acids that arrived on Earth via meteorites can also be found in many other places in the Universe.
“The Universe seems to love amino acids. Maybe if we found life on a different planet, it wouldn’t be so different.”
ZAP //
