scholarly journals Similar Yet Different–Structural and Functional Diversity among Arabidopsis thaliana LEA_4 Proteins

2020 ◽  
Vol 21 (8) ◽  
pp. 2794
Author(s):  
Patrick Knox-Brown ◽  
Tobias Rindfleisch ◽  
Anne Günther ◽  
Kim Balow ◽  
Anne Bremer ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Physicochemical Characteristics ◽  
Sequence Motifs ◽  
Lea Proteins ◽  
Membrane Stabilization ◽  
Functional Characteristics ◽  
Intrinsically Disordered ◽  
Thaw Cycle ◽  
Cellular Dehydration ◽  
Structural And Functional Properties

The importance of intrinsically disordered late embryogenesis abundant (LEA) proteins in the tolerance to abiotic stresses involving cellular dehydration is undisputed. While structural transitions of LEA proteins in response to changes in water availability are commonly observed and several molecular functions have been suggested, a systematic, comprehensive and comparative study of possible underlying sequence-structure-function relationships is still lacking. We performed molecular dynamics (MD) simulations as well as spectroscopic and light scattering experiments to characterize six members of two distinct, lowly homologous clades of LEA_4 family proteins from Arabidopsis thaliana. We compared structural and functional characteristics to elucidate to what degree structure and function are encoded in LEA protein sequences and complemented these findings with physicochemical properties identified in a systematic bioinformatics study of the entire Arabidopsis thaliana LEA_4 family. Our results demonstrate that although the six experimentally characterized LEA_4 proteins have similar structural and functional characteristics, differences concerning their folding propensity and membrane stabilization capacity during a freeze/thaw cycle are obvious. These differences cannot be easily attributed to sequence conservation, simple physicochemical characteristics or the abundance of sequence motifs. Moreover, the folding propensity does not appear to be correlated with membrane stabilization capacity. Therefore, the refinement of LEA_4 structural and functional properties is likely encoded in specific patterns of their physicochemical characteristics.

scholarly journals Molecular dynamics simulations and CD spectroscopy reveal hydration-induced unfolding of the intrinsically disordered LEA proteins COR15A and COR15B from Arabidopsis thaliana

2016 ◽  
Vol 18 (37) ◽  
pp. 25806-25816 ◽  
Author(s):  
Carlos Navarro-Retamal ◽  
Anne Bremer ◽  
Jans Alzate-Morales ◽  
Julio Caballero ◽  
Dirk K. Hincha ◽  
...  
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Arabidopsis Thaliana ◽  
Molecular Dynamics Simulations ◽  
Md Simulations ◽  
Cd Spectroscopy ◽  
Lea Proteins ◽  
Intrinsically Disordered ◽  
Dynamics Simulations ◽  
Crowded Environment

Unfolding of intrinsically unstructured full-length LEA proteins in a differentially crowded environment can be modeled by 30 ns MD simulations in accordance with experimental data.

scholarly journals Conserved Glycines Control Disorder and Function in the Cold-Regulated Protein, COR15A

Biomolecules ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 84 ◽  
Author(s):  
Oluwakemi Sowemimo ◽  
Patrick Knox-Brown ◽  
Wade Borcherds ◽  
Tobias Rindfleisch ◽  
Anja Thalhammer ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Intrinsically Disordered Protein ◽  
Helical Structure ◽  
Cd Spectroscopy ◽  
Protective Function ◽  
Intrinsically Disordered ◽  
Thaw Cycle ◽  
Cellular Dehydration ◽  
And Function ◽  
The Impact

Cold-regulated (COR) 15A is an intrinsically disordered protein (IDP) from Arabidopsis thaliana important for freezing tolerance. During freezing-induced cellular dehydration, COR15A transitions from a disordered to mostly α-helical structure. We tested whether mutations that increase the helicity of COR15A also increase its protective function. Conserved glycine residues were identified and mutated to alanine. Nuclear magnetic resonance (NMR) spectroscopy was used to identify residue-specific changes in helicity for wildtype (WT) COR15A and the mutants. Circular dichroism (CD) spectroscopy was used to monitor the coil–helix transition in response to increasing concentrations of trifluoroethanol (TFE) and ethylene glycol. The impact of the COR15A mutants on the stability of model membranes during a freeze–thaw cycle was investigated by fluorescence spectroscopy. The results of these experiments showed the mutants had a higher content of α-helical structure and the increased α-helicity improved membrane stabilization during freezing. Comparison of the TFE- and ethylene glycol-induced coil–helix transitions support our conclusion that increasing the transient helicity of COR15A in aqueous solution increases its ability to stabilize membranes during freezing. Altogether, our results suggest the conserved glycine residues are important for maintaining the disordered structure of COR15A but are also compatible with the formation of α-helical structure during freezing induced dehydration.

LEA proteins: IDPs with versatile functions in cellular dehydration tolerance

2012 ◽  
Vol 40 (5) ◽  
pp. 1000-1003 ◽  
Author(s):  
Dirk K. Hincha ◽  
Anja Thalhammer
Keyword(s):  
Late Embryogenesis Abundant ◽  
Plant Tissues ◽  
Lea Proteins ◽  
Plant Seed ◽  
Dehydration Tolerance ◽  
Intrinsically Disordered ◽  
Cellular Dehydration ◽  
Late Embryogenesis ◽  
Micro Organisms ◽  
Physiological And Biochemical

LEA (late embryogenesis abundant) proteins were originally described almost 30 years ago as accumulating late in plant seed development. They were later found to be induced in vegetative plant tissues under environmental stress conditions and also in desiccation-tolerant micro-organisms and invertebrates. Although they are widely assumed to play crucial roles in cellular dehydration tolerance, their physiological and biochemical functions are largely unknown. Most LEA proteins are predicted to be intrinsically disordered and this has been experimentally verified in several cases. In addition, some LEA proteins partially fold, mainly into α-helices, during drying or in the presence of membranes. Recent studies have concentrated on the potential roles of LEA proteins in stabilizing membranes or sensitive enzymes during freezing or drying, and the present review concentrates on these two possible functions of LEA proteins in cellular dehydration tolerance.

scholarly journals Characterization of the Heat-Stable Proteome During Seed Germination in Arabidopsis with Special Focus on LEA Proteins

2021 ◽  
Vol 22 (15) ◽  
pp. 8172
Author(s):  
Orarat Ginsawaeng ◽  
Michal Gorka ◽  
Alexander Erban ◽  
Carolin Heise ◽  
Franziska Brueckner ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seedling Establishment ◽  
Intrinsically Disordered Proteins ◽  
Late Embryogenesis Abundant ◽  
Disordered Proteins ◽  
Similar Proportion ◽  
Special Focus ◽  
Lea Proteins ◽  
Intrinsically Disordered ◽  
Heat Stable

During seed germination, desiccation tolerance is lost in the radicle with progressing radicle protrusion and seedling establishment. This process is accompanied by comprehensive changes in the metabolome and proteome. Germination of Arabidopsis seeds was investigated over 72 h with special focus on the heat-stable proteome including late embryogenesis abundant (LEA) proteins together with changes in primary metabolites. Six metabolites in dry seeds known to be important for seed longevity decreased during germination and seedling establishment, while all other metabolites increased simultaneously with activation of growth and development. Thermo-stable proteins were associated with a multitude of biological processes. In the heat-stable proteome, a relatively similar proportion of fully ordered and fully intrinsically disordered proteins (IDP) was discovered. Highly disordered proteins were found to be associated with functional categories development, protein, RNA and stress. As expected, the majority of LEA proteins decreased during germination and seedling establishment. However, four germination-specific dehydrins were identified, not present in dry seeds. A network analysis of proteins, metabolites and amino acids generated during the course of germination revealed a highly connected LEA protein network.

Troponins, intrinsic disorder, and cardiomyopathy

2016 ◽  
Vol 397 (8) ◽  
pp. 731-751 ◽  
Author(s):  
Insung Na ◽  
Min J. Kong ◽  
Shelby Straight ◽  
Jose R. Pinto ◽  
Vladimir N. Uversky
Keyword(s):  
Posttranslational Modifications ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Troponin T ◽  
Intrinsic Disorder ◽  
Functional Changes ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Structural And Functional Properties ◽  
Protein Intrinsic Disorder

Abstract Cardiac troponin is a dynamic complex of troponin C, troponin I, and troponin T (TnC, TnI, and TnT, respectively) found in the myocyte thin filament where it plays an essential role in cardiac muscle contraction. Mutations in troponin subunits are found in inherited cardiomyopathies, such as hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). The highly dynamic nature of human cardiac troponin and presence of numerous flexible linkers in its subunits suggest that understanding of structural and functional properties of this important complex can benefit from the consideration of the protein intrinsic disorder phenomenon. We show here that mutations causing decrease in the disorder score in TnI and TnT are significantly more abundant in HCM and DCM than mutations leading to the increase in the disorder score. Identification and annotation of intrinsically disordered regions in each of the troponin subunits conducted in this study can help in better understanding of the roles of intrinsic disorder in regulation of interactomes and posttranslational modifications of these proteins. These observations suggest that disease-causing mutations leading to a decrease in the local flexibility of troponins can trigger a whole plethora of functional changes in the heart.

scholarly journals Interplay of Structural Disorder and Short Binding Elements in the Cellular Chaperone Function of Plant Dehydrin ERD14

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1856
Author(s):  
Nikoletta Murvai ◽  
Lajos Kalmar ◽  
Bianka Szalaine Agoston ◽  
Beata Szabo ◽  
Agnes Tantos ◽  
...  
Keyword(s):  
Heat Stress ◽  
Intrinsically Disordered Proteins ◽  
Stress Protein ◽  
Structural Disorder ◽  
Disordered Proteins ◽  
Sequence Motifs ◽  
E Coli ◽  
Intrinsically Disordered

Details of the functional mechanisms of intrinsically disordered proteins (IDPs) in living cells is an area not frequently investigated. Here, we dissect the molecular mechanism of action of an IDP in cells by detailed structural analyses based on an in-cell nuclear magnetic resonance experiment. We show that the ID stress protein (IDSP) A. thaliana Early Response to Dehydration (ERD14) is capable of protecting E. coli cells under heat stress. The overexpression of ERD14 increases the viability of E. coli cells from 38.9% to 73.9% following heat stress (50 °C × 15 min). We also provide evidence that the protection is mainly achieved by protecting the proteome of the cells. In-cell NMR experiments performed in E. coli cells show that the protective activity is associated with a largely disordered structural state with conserved, short sequence motifs (K- and H-segments), which transiently sample helical conformations in vitro and engage in partner binding in vivo. Other regions of the protein, such as its S segment and its regions linking and flanking the binding motifs, remain unbound and disordered in the cell. Our data suggest that the cellular function of ERD14 is compatible with its residual structural disorder in vivo.

Deducing the functional characteristics of the human selenoprotein SELK from the structural properties of its intrinsically disordered C-terminal domain

2016 ◽  
Vol 12 (3) ◽  
pp. 758-772 ◽  
Author(s):  
Andrea Polo ◽  
Giovanni Colonna ◽  
Stefano Guariniello ◽  
Gennaro Ciliberto ◽  
Susan Costantini
Keyword(s):  
Structural Properties ◽  
Md Simulation ◽  
Functional Characteristics ◽  
Intrinsically Disordered ◽  
Terminal Domain

The results evidence that during MD simulation SELK presents a distribution of equilibrium conformers which continuously inter-change their conformations.

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