Despite their life expectancy of 1 to 3 years, tardigrades are aquatic micro-animals remarkable for their ability to survive for very long periods of time under stress conditions as diverse and lethal as extreme temperatures and pressures, desiccation or even irradiation. The molecular mechanisms that confer this unique resistance to extreme conditions have remained unknown until now, despite centuries-old fascination with tardigrades.
Researchers in the Protein Dynamics and Flexibility by NMR group have combined nuclear magnetic resonance, atomic force microscopy, and light and x-ray diffraction techniques to characterize the conformational and physical behaviour of an intrinsically disordered protein, unique to tardigrades, which plays an essential role in this environmental stress response. They were able to determine at the atomic scale that this protein has highly flexible disordered arms surrounding a long central helical domain whose behaviour is highly temperature dependent. This protein, which is highly flexible and dynamic under ambient conditions, transforms under stress conditions to form fibres, which in turn form a hydrogel. The researchers were able to sequester other proteins inside this gel formed by the tardigrade protein and showed that they retained their conformational behaviour. The exact mechanism by which the formation of such gels protects the organism is still unknown, but it is possible that the formation of such an intracellular matrix allows the maintenance of biomolecules in their functional state. This transformation of the cell environment, which is perfectly reversible when the stress is removed, provides a better understanding of the unique ability of tardigrades to survive conditions that would otherwise be fatal to life.
Intrinsically Disordered Tardigrade Proteins Self-Assemble into Fibrous Gels in Response to Environmental Stress. Malki A, Teulon JM, Camacho-Zarco AR, Chen SW, Adamski W, Maurin D, Salvi N, Pellequer JL, Blackledge M. Angewandte Chemie International Edition 2021 ;61(1):e202109961
Contact : Martin Blackledge (Protein Dynamics and Flexibility by NMR Group)