贝努小行星样本中首次检出痕量色氨酸

Core Insights - NASA and the University of Arizona's Lunar and Planetary Laboratory have detected trace amounts of tryptophan, an essential amino acid, in pristine samples from the asteroid Bennu, providing significant evidence for the hypothesis that the building blocks of life on Earth may originate from space [1][2] Group 1 - The asteroid Bennu, formed 4.6 billion years ago, has remained largely unchanged since the birth of the solar system, and NASA's OSIRIS-REx mission collected samples from its surface in 2020 for analysis [1] - Previous studies identified 33 amino acids in Bennu samples, with 14 of them being utilized by Earth life to construct proteins; the recent study confirms the presence of these 14 amino acids and detects trace amounts of tryptophan [1] - Tryptophan is significant as it is one of the more complex amino acids and is essential for human health, as it cannot be synthesized by the body and must be obtained through diet; this is the first detection of tryptophan in any meteorite or space sample [1] Group 2 - Researchers also detected five nucleobases, which are key components of DNA and RNA, indicating that both amino acids and nucleobases coexist in the same pristine celestial body [2] - The formation of these life precursor molecules is believed to be related to an ancient "hydration chemical factory," with Bennu samples containing abundant layered silicates that can only form in the presence of liquid water [2] - The presence of liquid water in Bennu's parent body suggests that it may have been rich in ammonia and other chemical components that could catalyze the gradual formation of amino acids and nucleotides from simple interstellar materials [2]