Centro de Astrobiología (CSIC-INTA), Ctra. de Ajalvir km. 4, Torrejón de Ardoz, 28850 Madrid, Spain.
Instituto de Ciencia Molecular (ICMoL), Universidad de Valencia, 46071 Valencia, Spain.
Phys Chem Chem Phys. 2022 Jul 21;24(28):16979-16987. doi: 10.1039/d2cp01703b.
In view of the existing controversy around the origin of the photosynthesis and, therefore, the first photosynthetic pigments, our work focuses on the theoretical study of a hypothetical first pigment, simpler than those existing today, that collects energy from solar radiation on Earth-like exoplanets. Our theoretical results show that there could exist geochemical conditions that allow the abiotic formation of a primeval pigment that might become sufficiently abundant in the early stages of habitable rocky exoplanets. These conditions would place this pigment before the appearance of life in a very young planet, thanks to chemical routes instead of biochemical transformations. Thus, our results may refute the currently accepted hypothesis that the complex biomolecules that allowed the photosynthesis to be carried out were synthesized through complex and evolved metabolic pathways. In addition, we show that the proposed primeval pigment, which we call Phot0, is also a precursor of the more evolved pigments known today on Earth and demonstrate, for the first time, an abiotic chemical route leading to tetrapyrroles not involving pyrrole derivatives. Our proposal places simple and very abundant raw materials in never-before-proposed geochemical conditions that lead to the formation of biomolecules of biological interest.
鉴于光合作用的起源以及由此产生的第一批光合色素一直存在争议，我们的工作集中于对假设的第一种色素进行理论研究，这种色素比今天存在的色素更简单，能够在类地系外行星上收集太阳辐射的能量。我们的理论结果表明，可能存在地球化学条件，允许在类地系外行星宜居的早期阶段形成一种原始色素，这种色素在生命出现之前可能会变得非常丰富。由于是化学途径而不是生化转化，这些条件使得这种色素在非常年轻的行星上早于生命出现。因此，我们的结果可能反驳了目前公认的假设，即允许光合作用进行的复杂生物分子是通过复杂和进化的代谢途径合成的。此外，我们还表明，我们称之为 Phot0 的提议原始色素也是地球上今天已知的更进化色素的前体，并首次展示了一种无需涉及吡咯衍生物的非生物化学途径生成四吡咯。我们的提议将简单且非常丰富的原料置于以前从未提出过的地球化学条件下，从而形成具有生物意义的生物分子。
