论文标题
同章：生命的先决条件或后果？
Homochirality: a prerequisite or consequence of life?
论文作者
论文摘要
氨基酸和核苷酸等生命的许多基础都是手性的，即与它们的镜像不同。当代生活选择并合成了两种可能的手段之一。但是，在非生物环境中，通常同样有许多左手和右手分子。如果同质性是生命的先决条件，则一定有物理或化学环境导致选择一定的偏好。相反，如果这是生命的结果，我们必须确定可能实现从外消旋到同种异体化学的过渡的可能途径。在讨论了观察性证据之后，我将回顾一下想法，即由于新兴的RNA世界中核苷酸的第一次聚合事件而出现任何义大度的同Ri。这些机制不仅限于核苷酸，而是肽作为RNA世界的先驱也可能发生。从这个意义上讲，同Rireal的问题与生命的起源紧密相关。未来的火星任务可能能够发现现存或灭绝生命的生物分子。因此，我们还将讨论可能在火星原位确定原始生命形式的手性的可能实验设置。
Many of the building blocks of life such as amino acids and nucleotides are chiral, i.e., different from their mirror image. Contemporary life selects and synthesizes only one of two possible handednesses. In an abiotic environment, however, there are usually equally many left- and right-handed molecules. If homochirality was a prerequisite of life, there must have been physical or chemical circumstances that led to the selection of a certain preference. Conversely, if it was a consequence of life, we must identify possible pathways for accomplishing a transition from a racemic to a homochiral chemistry. After a discussion of the observational evidence, I will review ideas where homochirality of any handedness could emerge as a consequence of the first polymerization events of nucleotides in an emerging RNA world. These mechanisms are not limited to nucleotides, but can also occur for peptides, as a precursor to the RNA world. The question of homochirality is, in this sense, intimately tied to the origin of life. Future Mars missions may be able to detect biomolecules of extant or extinct life. We will therefore also discuss possible experimental setups for determining the chirality of primitive life forms in situ on Mars.
