Li Yongda, Collins David A, Grintzalis Konstantinos
School of Biotechnology, Dublin City University, D09 Y5NO Dublin, Ireland.
Life (Basel). 2023 May 9;13(5):1150. doi: 10.3390/life13051150.
The search for life on other planets relies on the detection of biosignatures of life. Many macromolecules have been suggested as potential targets, among which are proteins that are considered vital components of life due to their essential roles in forming cellular structures, facilitating cellular communication and signaling, and catalyzing metabolic reactions. In this context, accurate quantification of protein signatures in soil would be advantageous, and while several proposed methods exist, which are limited by their sensitivity and specificity, their applicability needs further testing and validation. To this aim, we optimized a Bradford-based assay with high sensitivity and reproducibility and a simple protocol to quantify protein extracted from a Martian soil simulant. Methods for protein spiking, extraction, and recovery were optimized, using protein standards and bacterial proteins as representative models. The proposed method achieved high sensitivity and reproducibility. Taking into account that life remains could exist on the surface of Mars, which is subjected to UV radiation, a simulation of UV exposure was performed on a spiked soil simulant. UV radiation degraded the protein spike, thus highlighting the importance of searching for the remaining signal from degraded proteins. Finally, the applicability of the method was explored in relation to the storage of the reagent which was stable even up to 12 months, thus making its application possible for future planetary exploration missions.
对其他行星上生命的探索依赖于对生命生物特征的检测。许多大分子被认为是潜在的目标，其中蛋白质因其在形成细胞结构、促进细胞通讯和信号传导以及催化代谢反应中的重要作用而被视为生命的重要组成部分。在这种情况下，准确量化土壤中的蛋白质特征将具有优势，虽然存在几种提议的方法，但它们受到灵敏度和特异性的限制，其适用性需要进一步测试和验证。为此，我们优化了一种基于考马斯亮蓝法的检测方法，该方法具有高灵敏度和可重复性，且有一个简单的方案来量化从火星土壤模拟物中提取的蛋白质。使用蛋白质标准品和细菌蛋白作为代表性模型，对蛋白质加标、提取和回收方法进行了优化。所提出的方法具有高灵敏度和可重复性。考虑到火星表面可能存在生命遗迹，且该表面受到紫外线辐射，因此对加标土壤模拟物进行了紫外线照射模拟。紫外线辐射使加标的蛋白质降解，从而凸显了寻找降解蛋白质剩余信号的重要性。最后，探讨了该方法在试剂储存方面的适用性，该试剂即使长达12个月仍保持稳定，从而使其有可能应用于未来的行星探索任务。
