The Disordered Dehydrin and Its Role in Plant Protection: A Biochemical Perspective

Abstract

Dehydrins are intrinsically disordered proteins composed of several well conserved sequence motifs known as the Y-, S-, F-, and K-segments, the latter of which is a defining feature of all dehydrins. These segments are interspersed by regions of low sequence conservation and are organized modularly, which results in seven different architectures: Kn, SKn, YnSKn, YnKn, KnS, FnK and FnSKn. Dehydrins are expressed ubiquitously throughout the plant kingdom during periods of low intracellular water content, and are capable of improving desiccation tolerance in plants. In vitro evidence of dehydrins shows that they are involved in the protection of membranes, proteins and DNA from abiotic stresses. However, the molecular mechanisms by which these actions are achieved are as of yet somewhat unclear. With regards to macromolecule cryoprotection, there is evidence to suggest that a molecular shield-like protective effect is primarily influenced by the hydrodynamic radius of the dehydrin and to a lesser extent by the charge and hydrophobicity. The interaction between dehydrins and membranes is thought to be a surface-level, charge-based interaction that may help to lower the transition temperature, allowing membranes to maintain fluidity at low temperatures and preventing membrane fusion. In addition, dehydrins are able to protect DNA from damage, showing that these abiotic stress protection proteins have multiple roles.

The Effect of Positive Charge Distribution on the Cryoprotective Activity of Dehydrins

“…Under cold and/or drought conditions, these plants display enhanced growth and survival, and reduced electrolyte leakage and lipid peroxidation compared to their non-transgenic counterparts. While the mechanism by which LEA proteins accomplish this in vivo is uncertain, in vitro evidence has shown that LEA proteins are able to scavenge ions and stabilize biomacromolecules [ 3 , 11 , 12 , 13 ].…”

Uncharacterized protein c17orf80: a novel interactor of human mitochondrial nucleoids

“…C17orf80 may acquire more structural features upon binding to another protein or nucleic acids, as it is often true for intrinsically disordered proteins (van der Lee et al, 2014; Wright and Dyson, 2009). In various organisms, some proteins with such highly disordered sequences are involved in DNA damage protection (Hashimoto and Kunieda, 2017; Smith and Graether, 2022) and repair (Balasubramanian et al, 2022; López et al, 2020) via direct interaction with DNA.…”

Physiological, Structural, and Functional Insights Into the Cryoprotection of Membranes by the Dehydrins

“…One protective method that plants have evolved to combat this damage involves the expression of proteins known as dehydration-induced proteins (dehydrins). Dehydrins are a group of proteins expressed in plants to protect them from damage caused by dehydration stress (mainly drought, cold, salinity, and osmotic stresses; Graether and Boddington, 2014 ; Aziz et al, 2021 ; Riyazuddin et al, 2021 ; Smith and Graether, 2022 ). Dehydrins were originally identified as being group II proteins of the late embryogenesis abundant (LEA) proteins, a large family of proteins that are expressed in response to abiotic stress.…”

“…In addition to the K-segment, dehydrins also may contain three other motifs known as the Y-, F-, and S-segments. The motifs are present a variable number of times in dehydrins, resulting in several different architectures, specifically YSK n , FK n , FSK n , SK n , YK n , K n , and K n S ( Smith and Graether, 2022 ). In between, the conserved motifs are what are known as ϕ-segments; poorly conserved regions that mainly consist of small amino acids and are highly variable in length.…”