Dehydrins: Molecular Biology, Structure and Function
Plants can activate an array of various rescue responses when they have to survive environmental stresses such as low temperature or drought. One such response is the synthesis of various stress proteins such as chaperones and late embryonic abundant (LEA) proteins. Although the precise functions of many of the LEA proteins are unknown, the general hypothesis is that they stabilise membranes, proteins or other cellular structures by preventing stress denaturation.
The dehydrins, the group 2 LEA proteins, are plant-specific proteins that are highly expressed in response to low temperature, drought, high salt or to application of abscisic acid (ABA). Characteristic for the dehydrins are some highly conserved and repetitively scattered sequences of 7–17 amino acids called the K-, S-, Y- and lysine-rich segments.
The dehydrins are highly hydrophilic proteins and belong to the intrinsically disordered proteins, a class of proteins that lack a fixed 3D structure. Most disordered proteins can switch between non-functional disordered states to a functional state by a disorder-to-order transition. This conformational change is commonly induced upon binding to different cellular targets such as membranes or other proteins. Even though the molecular function of the dehydrins is yet unknown, there may be a relationship between a transiently formed structure and physiological function. Many of the proposed functions of dehydrins, for example chaperone activity, stabilising of membranes or metal chelating, involve interactions with cellular targets. However, to be able to structurally respond, the dehydrins must remain disordered in the changing and crowded interior of stressed plant cells.
KeywordsSodium Dodecyl Sulphate Sodium Dodecyl Sulphate Lipid Vesicle Knockout Mutant Helical Conformation
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