Knop Jim-Marcel, Mukherjee Sanjib K, Gault Stewart, Cockell Charles S, Winter Roland
Physical Chemistry I-Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Street 4a, 44227 Dortmund, Germany.
UK Centre for Astrobiology, SUPA School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK.
Life (Basel). 2022 May 2;12(5):677. doi: 10.3390/life12050677.
High pressure deep subsurface environments of Mars may harbor high concentrations of dissolved salts, such as perchlorates, yet we know little about how these salts influence the conditions for life, particularly in combination with high hydrostatic pressure. We investigated the effects of high magnesium perchlorate concentrations compared to sodium and magnesium chloride salts and high pressure on the conformational dynamics and stability of double-stranded B-DNA and, as a representative of a non-canonical DNA structure, a DNA-hairpin (HP), whose structure is known to be rather pressure-sensitive. To this end, fluorescence spectroscopies including single-molecule FRET methodology were applied. Our results show that the stability both of the B-DNA as well as the DNA-HP is largely preserved at high pressures and high salt concentrations, including the presence of chaotropic perchlorates. The perchlorate anion has a small destabilizing effect compared to chloride, however. These results show that high pressures at the kbar level and perchlorate anions can modify the stability of nucleic acids, but that they do not represent a barrier to the gross stability of such molecules in conditions associated with the deep subsurface of Mars.
火星的高压深层地下环境可能含有高浓度的溶解盐，如高氯酸盐，但我们对这些盐如何影响生命条件知之甚少，尤其是在与高静水压力共同作用的情况下。我们研究了与氯化钠和氯化镁盐相比，高浓度的高氯酸镁以及高压对双链B-DNA构象动力学和稳定性的影响，并且作为非经典DNA结构的代表，研究了对一种DNA发夹结构（HP）的影响，已知该结构对压力相当敏感。为此，我们应用了包括单分子荧光共振能量转移方法在内的荧光光谱技术。我们的结果表明，在高压和高盐浓度条件下，包括存在离液序列高氯酸盐时，B-DNA以及DNA-HP的稳定性在很大程度上得以保留。然而，与氯离子相比，高氯酸根阴离子具有较小的去稳定作用。这些结果表明，千巴级别的高压和高氯酸根阴离子可以改变核酸的稳定性，但在与火星深层地下相关的条件下，它们并不构成此类分子总体稳定性的障碍。
