Scientists have uracil – One parts RNA, the large molecule that contains instructions for the structure and function of living things – was found in samples from the Ryugu asteroid collected by the Japanese spacecraft Hayabusa2. Nicotinic acid, also known as vitamin B3 and an important cofactor for metabolism in living organisms, was also detected in the samples. The discovery, made by an international team led by Yasuhiro Ohba of Hokkaido University (Japan), supports the hypothesis that the building blocks of life originate in space, possibly brought to Earth by meteorites (Nature CommunicationsMarch 21).
Particles like these have already been detected in some carbon-rich meteorites, but the question has always been whether “contamination” with terrestrial material could not have occurred. Since Hayabusa2 recovered two samples directly from the Ryugu asteroid and delivered them to Earth in sealed capsules, contamination can be ruled out.
The researchers extracted the particles by soaking the Ryugu particles in hot water and using them liquid chromatography And mass spectrometry to analyze. Uracil was found in the samples in small amounts (6 to 31 ppb), and vitamin B3 in larger amounts (49 to 99 ppb). In addition, other biomolecules, including several amino acids, amines and carboxylic acids, have also been shown to play a role in proteomics and metabolism. The detected compounds are similar to, but not identical to, those previously discovered in carbon-rich meteorites.
The team suspects that the differences between the samples, which come from different places in Ryugu, are due to exposure to space. Scientists also suspect that nitrogenous compounds are composed, at least in part, of simpler molecules such as ammonia, formaldehyde, and hydrogen cyanide. Although it is not present in the Ryugu samples, it is known to be present in the comet’s ice. This could mean that Ryugu was originally a comet or some other object that formed at lower temperatures. (EE)
