scholarly journals Preferential adsorption to air–water interfaces: a novel cryoprotective mechanism for LEA proteins

2019 ◽  
Vol 476 (7) ◽  
pp. 1121-1135 ◽  
Author(s):  
Fanny Yuen ◽  
Matthew Watson ◽  
Robert Barker ◽  
Isabelle Grillo ◽  
Richard K. Heenan ◽  
...  
Keyword(s):  
Intrinsically Disordered Proteins ◽  
Citrate Synthase ◽  
Abiotic Stress Tolerance ◽  
Interfacial Area ◽  
Disordered Proteins ◽  
General Mechanism ◽  
Lea Proteins ◽  
Freeze Thaw ◽  
Intrinsically Disordered ◽  
Induced Aggregation

Abstract Late embryogenesis abundant (LEA) proteins comprise a diverse family whose members play a key role in abiotic stress tolerance. As intrinsically disordered proteins, LEA proteins are highly hydrophilic and inherently stress tolerant. They have been shown to stabilise multiple client proteins under a variety of stresses, but current hypotheses do not fully explain how such broad range stabilisation is achieved. Here, using neutron reflection and surface tension experiments, we examine in detail the mechanism by which model LEA proteins, AavLEA1 and ERD10, protect the enzyme citrate synthase (CS) from aggregation during freeze–thaw. We find that a major contributing factor to CS aggregation is the formation of air bubbles during the freeze–thaw process. This greatly increases the air–water interfacial area, which is known to be detrimental to folded protein stability. Both model LEA proteins preferentially adsorb to this interface and compete with CS, thereby reducing surface-induced aggregation. This novel surface activity provides a general mechanism by which diverse members of the LEA protein family might function to provide aggregation protection that is not specific to the client protein.

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.

scholarly journals The N-Terminal Region of Soybean PM1 Protein Protects Liposomes during Freeze-Thaw

2020 ◽  
Vol 21 (15) ◽  
pp. 5552
Author(s):  
Liyi Chen ◽  
Yajun Sun ◽  
Yun Liu ◽  
Yongdong Zou ◽  
Jianzi Huang ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Membrane Fusion ◽  
Terminal Region ◽  
Freezing Stress ◽  
Disordered Proteins ◽  
Distribution Analysis ◽  
Protective Function ◽  
Freeze Thaw ◽  
Intrinsically Disordered ◽  
Induced Aggregation

Late embryogenesis abundant (LEA) group 1 (LEA_1) proteins are intrinsically disordered proteins (IDPs) that play important roles in protecting plants from abiotic stress. Their protective function, at a molecular level, has not yet been fully elucidated, but several studies suggest their involvement in membrane stabilization under stress conditions. In this paper, the soybean LEA_1 protein PM1 and its truncated forms (PM1-N: N-terminal half; PM1-C: C-terminal half) were tested for the ability to protect liposomes against damage induced by freeze-thaw stress. Turbidity measurement and light microscopy showed that full-length PM1 and PM1-N, but not PM1-C, can prevent freeze-thaw-induced aggregation of POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) liposomes and native thylakoid membranes, isolated from spinach leaves (Spinacia oleracea). Particle size distribution analysis by dynamic light scattering (DLS) further confirmed that PM1 and PM1-N can prevent liposome aggregation during freeze-thaw. Furthermore, PM1 or PM1-N could significantly inhibit membrane fusion of liposomes, but not reduce the leakage of their contents following freezing stress. The results of proteolytic digestion and circular dichroism experiments suggest that PM1 and PM1-N proteins bind mainly on the surface of the POPC liposome. We propose that, through its N-terminal region, PM1 functions as a membrane-stabilizing protein during abiotic stress, and might inhibit membrane fusion and aggregation of vesicles or other endomembrane structures within the plant cell.

scholarly journals Interactions between the Intrinsically Disordered Regions of hnRNP-A2 and TDP-43 Accelerate TDP-43′s Conformational Transition

2020 ◽  
Vol 21 (16) ◽  
pp. 5930
Author(s):  
Wan-Chin Chiang ◽  
Ming-Hsuan Lee ◽  
Tsai-Chen Chen ◽  
Jie-rong Huang
Keyword(s):  
Intrinsically Disordered Proteins ◽  
Rna Binding ◽  
Conformational Transition ◽  
Rna Binding Proteins ◽  
Sequence Similarity ◽  
Disordered Proteins ◽  
General Mechanism ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Disordered Regions

Most biological functions involve protein–protein interactions. Our understanding of these interactions is based mainly on those of structured proteins, because encounters between intrinsically disordered proteins (IDPs) or proteins with intrinsically disordered regions (IDRs) are much less studied, regardless of the fact that more than half eukaryotic proteins contain IDRs. RNA-binding proteins (RBPs) are a large family whose members almost all have IDRs in addition to RNA binding domains. These IDRs, having low sequence similarity, interact, but structural details on these interactions are still lacking. Here, using the IDRs of two RBPs (hnRNA-A2 and TDP-43) as a model, we demonstrate that the rate at which TDP-43′s IDR undergoes the neurodegenerative disease related α-helix-to-β-sheet transition increases in relation to the amount of hnRNP-A2′s IDR that is present. There are more than 1500 RBPs in human cells and most of them have IDRs. RBPs often join the same complexes to regulate genes. In addition to the structured RNA-recognition motifs, our study demonstrates a general mechanism through which RBPs may regulate each other’s functions through their IDRs.

Intrinsically disordered chaperones in plants and animalsThis paper is one of a selection of papers published in this special issue entitled “Canadian Society of Biochemistry, Molecular & Cellular Biology 52nd Annual Meeting — Protein Folding: Principles and Diseases” and has undergone the Journal's usual peer review process.

2010 ◽  
Vol 88 (2) ◽  
pp. 167-174 ◽  
Author(s):  
Peter Tompa ◽  
Denes Kovacs
Keyword(s):  
Stress Proteins ◽  
Intrinsically Disordered Proteins ◽  
Peer Review Process ◽  
Plant Stress ◽  
Late Embryogenesis Abundant ◽  
Disordered Proteins ◽  
Lea Proteins ◽  
Intrinsically Disordered ◽  
And Function

Intrinsically disordered proteins (IDPs) are widespread in eukaryotes and fulfill important functions associated with signaling and regulation. Recent evidence points to a special and thus largely disrespected functional capacity of IDPs—that they can assist the folding of other proteins and prevent their aggregation, i.e., that they can act as chaperones. In this paper, we survey current information available on this phenomenon, with particular focus on (i) the structure and function of IDPs in general, (ii) disordered chaperones in plants, (iii) disordered chaperones in other organisms spanning from insects to mammals, (iv) the possible mechanisms of action of disordered chaperones, and (v) the possibility of two-faced (Janus) chaperone activity of disordered chaperones, which can assist the folding of both RNA and protein substrates. The evidence is most conclusive in the case of plant stress proteins, such as late embryogenesis abundant (LEA) proteins or dehydrins. We will show that the cellular function of LEA proteins in mitigating the damage caused by stress is clear; nevertheless, experiments carried out in vivo must be extended and the molecular mechanism of the action of IDP chaperones also requires clarification. Using these details, we chart out how far the field has progressed only to emphasize the long road ahead before chaperone function can be firmly established as part of the physiological mechanistic arsenal of the emerging group of IDPs.

scholarly journals Plant Group II LEA Proteins: Intrinsically Disordered Structure for Multiple Functions in Response to Environmental Stresses

Biomolecules ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1662
Author(s):  
Mughair Abdul Aziz ◽  
Miloofer Sabeem ◽  
Sangeeta Kutty Mullath ◽  
Faical Brini ◽  
Khaled Masmoudi
Keyword(s):  
Intrinsically Disordered Proteins ◽  
Association Studies ◽  
Environmental Stresses ◽  
Disordered Proteins ◽  
Genome Wide Association Studies ◽  
Lea Proteins ◽  
Lea Genes ◽  
Intrinsically Disordered ◽  
Wide Range ◽  
Group Ii

In response to various environmental stresses, plants have evolved a wide range of defense mechanisms, resulting in the overexpression of a series of stress-responsive genes. Among them, there is certain set of genes that encode for intrinsically disordered proteins (IDPs) that repair and protect the plants from damage caused by environmental stresses. Group II LEA (late embryogenesis abundant) proteins compose the most abundant and characterized group of IDPs; they accumulate in the late stages of seed development and are expressed in response to dehydration, salinity, low temperature, or abscisic acid (ABA) treatment. The physiological and biochemical characterization of group II LEA proteins has been carried out in a number of investigations because of their vital roles in protecting the integrity of biomolecules by preventing the crystallization of cellular components prior to multiple stresses. This review describes the distribution, structural architecture, and genomic diversification of group II LEA proteins, with some recent investigations on their regulation and molecular expression under various abiotic stresses. Novel aspects of group II LEA proteins in Phoenix dactylifera and in orthodox seeds are also presented. Genome-wide association studies (GWAS) indicated a ubiquitous distribution and expression of group II LEA genes in different plant cells. In vitro experimental evidence from biochemical assays has suggested that group II LEA proteins perform heterogenous functions in response to extreme stresses. Various investigations have indicated the participation of group II LEA proteins in the plant stress tolerance mechanism, spotlighting the molecular aspects of group II LEA genes and their potential role in biotechnological strategies to increase plants’ survival in adverse environments.

Sequence Specificity Despite Intrinsic Disorder: How a Disease-Associated Val/Met Polymorphism Shifts Tertiary Interactions in a Long Disordered Protein

2019 ◽  
Author(s):  
Ruchi Lohia ◽  
Reza Salari ◽  
Grace Brannigan
Keyword(s):  
Secondary Structure ◽  
Electrostatic Interactions ◽  
Intrinsically Disordered Proteins ◽  
Disordered Proteins ◽  
Sequence Specificity ◽  
Intrinsically Disordered ◽  
Specific Effects ◽  
Heterogeneous Polymer ◽  
Non Local ◽  
Dynamics Simulations

<div>The role of electrostatic interactions and mutations that change charge states in intrinsically disordered proteins (IDPs) is well-established, but many disease-associated mutations in IDPs are charge-neutral. The Val66Met single nucleotide polymorphism (SNP) encodes a hydrophobic-to-hydrophobic mutation at the midpoint of the prodomain of precursor brain-derived neurotrophic factor (BDNF), one of the earliest SNPs to be associated with neuropsychiatric disorders, for which the underlying molecular mechanism is unknown. Here we report on over 250 μs of fully-atomistic, explicit solvent, temperature replica exchange molecular dynamics simulations of the 91 residue BDNF prodomain, for both the V66 and M66 sequence.</div><div>The simulations were able to correctly reproduce the location of both local and non-local secondary changes due to the Val66Met mutation when compared with NMR spectroscopy. We find that the local structure change is mediated via entropic and sequence specific effects. We show that the highly disordered prodomain can be meaningfully divided into domains based on sequence alone. Monte Carlo simulations of a self-excluding heterogeneous polymer, with monomers representing each domain, suggest the sequence would be effectively segmented by the long, highly disordered polyampholyte near the sequence midpoint. This is qualitatively consistent with observed interdomain contacts within the BDNF prodomain, although contacts between the two segments are enriched relative to the self-excluding polymer. The Val66Met mutation increases interactions across the boundary between the two segments, due in part to a specific Met-Met interaction with a Methionine in the other segment. This effect propagates to cause the non-local change in secondary structure around the second methionine, previously observed in NMR. The effect is not mediated simply via changes in inter-domain contacts but is also dependent on secondary structure formation around residue 66, indicating a mechanism for secondary structure coupling in disordered proteins. </div>

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