Departamento de Evolución Molecular, Spanish Centre for Astrobiology, (CAB-CSIC), Instituto Nacional de Técnica Aeroespacial (INTA), Carretera de Ajalvir km 4, Torrejón de Ardoz, 28850, Madrid, Spain.
Departamento de Planetología y habitabilidad, Spanish Centre for Astrobiology, (CAB-CSIC), Instituto Nacional de Técnica Aeroespacial (INTA), Carretera de Ajalvir km 4, Torrejón de Ardoz, 28850, Madrid, Spain.
Sci Rep. 2022 Aug 11;12(1):13677. doi: 10.1038/s41598-022-17802-y.
The Martian subsurface is more favorable for organic preservation than its surface because of the shielding effect of rocks from cosmic rays and UV radiation with increasing depth. Nevertheless, the natural radioactivity on Mars owing to U, Th, and K must be considered to study the possible extant and/or extinct life. Here, we demonstrate the importance of natural radiation on the amino acid glycine in two different chemical environments, GlyFeSO 5HO and GlyMgSO 5HO, which are coordination compounds considered relevant to Mars. The results show that after a 600 kGy dose of gamma radiation, glycine was more stable when it bonded to Mg in the GlyMgSO 5HO coordination compound, it was less stable when it bonded to Fe in the GlyFeSO 5HO compound. Studies on the effects of gamma radiation on preservation of organic molecules bound to minerals and other potential compounds on Mars are significantly important in the search for biosignatures.
火星的地下环境比其表面更有利于有机物质的保存，因为随着深度的增加，岩石对宇宙射线和紫外线辐射具有屏蔽作用。然而，由于铀、钍和钾，火星上的天然放射性必须加以考虑，以研究可能存在的和/或已灭绝的生命。在这里，我们展示了自然辐射对两种不同化学环境中的氨基酸甘氨酸的重要性，即甘氨酸-硫酸亚铁五水合物和甘氨酸-硫酸镁五水合物，这两种配位化合物与火星有关。结果表明，在 600kGy 的γ射线剂量下，当甘氨酸与 GlyMgSO 5HO 配位化合物中的 Mg 结合时，其稳定性更高，而当与 GlyFeSO 5HO 化合物中的 Fe 结合时，其稳定性更低。研究γ辐射对火星上结合矿物质和其他潜在化合物的有机分子保存的影响，对于寻找生物特征具有重要意义。
