Oak Ridge Associated Universities, Greenbelt, MD 20771, USA.
Chem Soc Rev. 2012 Aug 21;41(16):5459-72. doi: 10.1039/c2cs35109a. Epub 2012 Jun 15.
The discoveries of amino acids of extraterrestrial origin in many meteorites over the last 50 years have revolutionized the Astrobiology field. A variety of non-terrestrial amino acids similar to those found in life on Earth have been detected in meteorites. A few amino acids have even been found with chiral excesses, suggesting that meteorites could have contributed to the origin of homochirality in life on Earth. In addition to amino acids, which have been productively studied for years, sugar-like molecules, activated phosphates, and nucleobases have also been determined to be indigenous to numerous meteorites. Because these molecules are essential for life as we know it, and meteorites have been delivering them to the Earth since accretion, it is plausible that the origin(s) of life on Earth were aided by extraterrestrially-synthesized molecules. Understanding the origins of life on Earth guides our search for life elsewhere, helping to answer the question of whether biology is unique to Earth. This tutorial review focuses on meteoritic amino acids and nucleobases, exploring modern analytical methods and possible formation mechanisms. We will also discuss the unique window that meteorites provide into the chemistry that preceded life on Earth, a chemical record we do not have access to on Earth due to geologic recycling of rocks and the pervasiveness of biology across the planet. Finally, we will address the future of meteorite research, including asteroid sample return missions.
在过去的 50 年中，在许多陨石中发现了外星起源的氨基酸，这彻底改变了天体生物学领域。在陨石中检测到了多种与地球上生命中发现的相似的非地外氨基酸。甚至发现了一些具有手性过剩的氨基酸，这表明陨石可能有助于地球上生命同源手性的起源。除了多年来一直在进行深入研究的氨基酸外，还确定了糖样分子、活化磷酸盐和核苷碱基也是许多陨石的固有成分。由于这些分子是我们所知生命所必需的，而且陨石自吸积以来一直在向地球输送这些分子，因此可以合理地认为，地球上生命的起源得益于外星合成的分子。了解地球上生命的起源指导着我们在其他地方寻找生命，有助于回答生物学是否仅存在于地球上的问题。本教程综述重点介绍了陨石中的氨基酸和核苷碱基，探讨了现代分析方法和可能的形成机制。我们还将讨论陨石提供的独特窗口，了解地球生命之前的化学情况，由于地球岩石的地质循环和生物的普遍存在，我们无法在地球上获得这种化学记录。最后，我们将探讨陨石研究的未来，包括小行星样本返回任务。
