The desiccation tolerance of tardigrades has recently been attributed to the unique protective capabilities of a family of intrinsically disordered, tardigrade-specific cytoplasmic abundant heat-soluble (CAHS) proteins. CAHS-D plays an essential role in maintaining the viability of tardigrades as well as the in vitro activity of a variety of enzymes through gelation and vitrification. Though the unique biochemical properties of CAHS-D and their protective contributions have been thoroughly investigated, the tolerance of these phase transitions to different cosolutes has not yet been validated in biochemically complex systems. We examine the viscoelastic properties of the CAHS-D gel in physiologically relevant conditions using microrheology techniques. In addition, we probe the gelation and enzyme protection in the presence of heterogeneous CAHS-D variants, which simulate the many varieties found endogenously within tardigrades. Through these investigations, we validate the robustness of the protective mechanism of CAHS-D in a native-like environment and expand upon its use in complex biotechnological applications.
Zhang et al. (Sun,) studied this question.