The ability to adapt to changes in the environment is crucial to the survival of plants since they can not just walk away from danger. The plants have developed an array of different strategies on how to stay alive in harsh surroundings. On a molecular level this usually means to keep the proteins and membranes in least perturbed form to sustain their functions.
In the past few years a new class of proteins has gained attention - the intrinsically disordered proteins. These proteins have no fixed tertiary structure under physiological conditions but seem nevertheless to perform specific functions in different cellular processes. Out of protein sequences from the Arabidopsis genome, 650 (8%) were predicted to lack ordered structure. So how may disordered proteins function? In some cases, disordered proteins have been observed to adapt such well-ordered structure as they bind to biological target molecules such as other proteins, RNA or DNA. The dehydrins represent a specific class of proteins that seems ubiquitously expressed under conditions of stress, e.g. drought, salt, low temperature or applied ABA. A characteristic, but poorly understood, feature of the dehydrins is some highly conserved and often repetitively occurring sequences, i.e. the K-, S- and Y-segments. Speculations about the molecular function of the dehydrins have been directed along the following lines: 1. Dehydrins may form amphiphatic helices that stabilise the membranes. 2. Chaperone action. 3. Antifreeze properties. 4. Coordinating water to prevent dehydration. 5. Metal- and Ca- binding .
This project is aimed to shed further light on the biological and molecular function of the dehydrins through:
1. Studies of how their structure and constituent segments respond to physiologically relevant perturbations, like temperature, molecular crowding, dilution/concentration etc. etc.
2. Systematic search for biological ligands.
3. In a recent project we study if the dehydrins act as chaperones, that is to bind to other proteins and prevent them from denature.
Vaughan, C.K., Harryson, P., Buckle, A.M., Fersht, A.R. () A structural double-mutant cycle: estimating the strength of a buried salt bridge in barnase. Acta Crystallogr D Biol Crystallogr 58: 591-600.
