PhD defence: Structural and dynamic characterisation of the intrinsic disorder, fibrillar assemblies and gelation properties of a dehydration-protective tardigrade protein

By Anas Malki (-IBS/Protein Dynamics and Flexibility by NMR Group)

Tardigrades are microscopic animals able to survive extreme stress conditions, and in particular severe and prolonged dehydration. Recently, a family of intrinsically disordered proteins, the Cytosolic Abundant Heat-Soluble (CAHS) proteins, were shown to have a critical role in the survival of tardigrades of the species Hybsibius exemplaris. Indeed, the expression of these proteins by cells other than tardigrades, such as yeast or human cells, confers enhanced resistance to dehydration. Understanding the mechanisms that enable this survival to dehydration is therefore of major interest for the survival of agricultural crops during drought, for the preservation of food, drugs or even biological tissues. This thesis studied the biophysical mechanisms that enable one of the most protective proteins, CAHS-8 from Hybsibius exemplaris, to adapt to dehydration and protect its host organism. For this state-of-the-art Nuclear Magnetic Resonance spectroscopy was used, as well as microscopy and scattering techniques.