High-purity isolation and chemical composition of stabilisomes from thermophilic cyanobacteria

Thermophilic cyanobacteria are not only fundamental models for investigating thermotolerance mechanisms but also a valuable reservoir for the development of novel thermophilic bioresources. Progress in both of these areas, however, is contingent upon the precise characterization of their key subcellular organelles, such as the intracellular polyphosphate-rich granules which we term stabilisomes. The lack of a high-purity, structure-preserving isolation method has been a major technical bottleneck hindering such research. This study describes a high-fidelity, structure-preserving purification strategy, boosting the granule-to-protein yield by over 10,000-fold compared with conventional methods. The high fidelity of this method is confirmed by the retention of complex proteomic (937 proteins) and metabolomic (1,076 metabolites) signatures. Building on this, subsequent quantitative analysis across cyanobacteria at 7 hot spring sampling sites revealed a conserved core chemical composition dominated by polyphosphate (21.1%-36.4%), proteins (9.9%-20.0%), amino acids (1.6%-7.4%), and lipids (12.0%-21.0%), which nevertheless showed significant variabilitiy in the abundance of these components across species. This work establishes a robust methodological framework for isolating prokaryotic stress-responsive organelles, lays the foundation for mechanistic investigations into microbial adaptation, and serves as a prerequisite for exploring the biomedical applications of these organelles.

嗜热蓝藻不仅是研究耐热机制的基础模型，亦是开发新型嗜热生物资源的宝贵库藏。然而，上述两大领域的研究进展均有赖于对其关键亚细胞细胞器的精准表征——例如我们将胞内富多磷酸盐颗粒命名为稳定体（stabilisomes）。此前缺乏高纯度且可维持结构完整性的分离方法，一直是阻碍该领域研究的核心技术瓶颈。本研究报道了一种高保真、维持结构完整性的纯化策略，相较于传统方法，可将颗粒-蛋白得率提升10000倍以上。该方法的高保真特性可通过保留完整的蛋白质组（937种蛋白）与代谢组（1076种代谢物）特征谱得到验证。在此基础上，研究人员对7个温泉采样点的蓝藻开展定量分析，结果显示其核心化学组成较为保守，主要成分为多磷酸盐（21.1%~36.4%）、蛋白质（9.9%~20.0%）、氨基酸（1.6%~7.4%）与脂质（12.0%~21.0%），但不同物种间各组分的丰度存在显著差异。本研究为原核生物应激响应细胞器的分离构建了稳健的方法学框架，为微生物适应性的机制研究奠定了基础，同时也为探索这类细胞器的生物医学应用提供了必要前提。