RNA building block discovered on asteroid Ryugu

The discovery supports the idea that important building blocks of life are created in space and may have been deposited on Earth by space rocks.

During an analysis of material from the asteroid Ryugu, scientists came across uracil, among other things. A special discovery. Uracil is a building block of ribonucleic acid, better known as RNA: a molecule that contains instructions for the “building” and functioning of organisms.

Vitamin B3
In addition to uracil, the researchers also encountered nicotinic acid, also known as vitamin B3, in the material. This substance plays an important role in metabolism.

Other biological molecules
“We found uracil in small amounts in the samples,” says researcher Yasuhiro Oba. This concerns concentrations of 6 to 32 ppb (parts per billion). “Vitamin B3 was more abundant, with a concentration of 49 to 99 ppb. Additionally, we also found other organic molecules in the sample. Including a selection of amino acids that are part of proteins or play a role in metabolism.

Ryugu
As mentioned, the researchers discovered the substances contained in the materials of Ryugu. These materials were obtained when the space shuttle Hayabusa2 descended to the surface of the asteroid in 2019 to sample it. The collected material was then deposited on Earth in December 2020 for analysis.

Valuable samples
Of course, this is not the first time that researchers have studied the composition of meteorites. But before, they had to do it mainly with space rocks that had exploded on the surface of the earth. However, samples that are now collected from a space rock that is still in space are somehow much more valuable, Oba explains. “Scientists have already discovered nucleobases and vitamins in certain carbon-rich meteorites, but the question has always been whether they had not been contaminated (by these substances, editor’s note) by exposure to the Earth’s environment.” In other words, it could not be completely ruled out that these nucleobases and vitamins ended up on these space rocks after meteorites landed. “Since Hayabusa2 took two samples from the asteroid Ryugu and delivered them to Earth in sealed capsules, contamination can be ruled out.”

Theory
Of Discovery that Ryugu, still in space, harbors vitamins and nucleobases, the theory that important building blocks of life – such as nucleobases – form in space gains traction. It is assumed that these building blocks of life were deposited on Earth by asteroids and comets in the past. There they then contributed to the creation of life.

Later this year, the US space probe OSIRIS-REx will deliver materials collected from the asteroid Bennu to Earth. By studying the composition of this asteroid using these materials and comparing it to that of Ryugu, scientists hope to strengthen and, if necessary, refine the theories mentioned above.