Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA.
Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA, 02115, USA.
Commun Biol. 2024 May 25;7(1):633. doi: 10.1038/s42003-024-06336-w.
Tardigrades, microscopic animals that survive a broad range of environmental stresses, express a unique set of proteins termed tardigrade-specific intrinsically disordered proteins (TDPs). TDPs are often expressed at high levels in tardigrades upon desiccation, and appear to mediate stress adaptation. Here, we focus on the proteins belonging to the secreted family of tardigrade proteins termed secretory-abundant heat soluble ("SAHS") proteins, and investigate their ability to protect diverse biological structures. Recombinantly expressed SAHS proteins prevent desiccated liposomes from fusion, and enhance desiccation tolerance of E. coli and Rhizobium tropici upon extracellular application. Molecular dynamics simulation and comparative structural analysis suggest a model by which SAHS proteins may undergo a structural transition upon desiccation, in which removal of water and solutes from a large internal cavity in SAHS proteins destabilizes the beta-sheet structure. These results highlight the potential application of SAHS proteins as stabilizing molecules for preservation of cells.
缓步动物是一种能够在广泛的环境压力下生存的微观动物，它们表达了一组独特的蛋白质，称为缓步动物特异性无规卷曲蛋白质（TDP）。TDP 在缓步动物干燥时通常会高水平表达，并似乎介导了应激适应。在这里，我们专注于属于缓步动物分泌蛋白家族的蛋白质，称为分泌丰富的热可溶性（“SAHS”）蛋白，并研究它们保护多种生物结构的能力。重组表达的 SAHS 蛋白可防止干燥的脂质体融合，并在细胞外应用时增强大肠杆菌和热带根瘤菌的干燥耐受性。分子动力学模拟和比较结构分析提出了一个模型，即 SAHS 蛋白在干燥时可能会发生结构转变，其中从 SAHS 蛋白的大内部腔中去除水和溶质会破坏β-折叠结构。这些结果强调了 SAHS 蛋白作为稳定分子在细胞保存中的潜在应用。
