The Ryugu asteroid contains an RNA ingredient

March 21 () –

Samples from the Ryugu asteroid contain nitrogenous organic compounds, including the uracil nucleobase, part of the RNA: instructions on how to build and operate living organisms.

Nicotinic acid, also known as vitamin B3 or niacin, which is an important cofactor for the metabolism of living organisms, was also detected in the same samples, brought back to Earth by the Hayabusa2 mission of the Japanese space agency, JAXA.

This discovery by an international team, led by Associate Professor Yasuhiro Oba at Hokkaido University, adds to the evidence that the building blocks important to life are created in space and could have been brought to Earth by meteorites. . The findings were published in the journal Nature Communications.

“Scientists have previously found nucleobases and vitamins in certain carbon-rich meteorites, but there has always been the question of contamination from exposure to Earth’s environment,” Oba explained. “Since the Hayabusa2 spacecraft collected two samples directly from the Ryugu asteroid and delivered them to Earth in sealed capsules, contamination can be ruled out.

The researchers extracted these molecules by immersing the Ryugu particles in hot water, followed by analysis using liquid chromatography along with high-resolution mass spectrometry. This revealed the presence of uracil and nicotinic acid, as well as other nitrogen-containing organic compounds.

“We found uracil in the samples in small amounts, in the range of 6 to 32 parts per billion (ppb), while vitamin B3 was more abundant, in the range of 49 to 99 ppb,” Oba explained. it’s a statement. “Other biological molecules were also found in the sample, including a selection of amino acids, amines, and carboxylic acids, which are found in protein and metabolism, respectively.” The detected compounds they are similar but not identical to those previously discovered in carbon-rich meteorites.

The team hypothesizes that the difference in concentrations in the two samples, collected at different locations on Ryugu, is likely due to exposure to the extreme environments of space. They also hypothesized that nitrogen-containing compounds formed, at least in part, from simpler molecules such as ammonia, formaldehyde, and hydrogen cyanide. While these were not detected in the Ryugu samples, they are known to be present in cometary ice, and Ryugu could have originated as a comet or other main body that was present in low-temperature environments.

“The discovery of uracil in the Ryugu samples gives strength to current theories about the origin of nucleobases on the early Earth,” concludes Oba. “NASA’s OSIRIS-REx mission will return samples of asteroid Bennu this year, and a comparative study of the composition of these asteroids It will provide more data to develop these theories.”