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Preferential adsorption to air-water interfaces: a novel cryoprotective mechanism for LEA proteins

Published version
Peer-reviewed

Type

Article

Change log

Authors

Routh, Alexander 
Yuen, Fanny 
Watson, Matthew 
Barker, Robert 
grillo, Isabelle 

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 stabilize multiple client proteins under a variety of stresses, but current hypotheses do not fully explain how such broad range stabilization 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 from aggregation during freeze-thaw. We find that a major contributing factor to citrate synthase 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 citrate synthase, 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.

Description

Keywords

anhydrobiosis, freeze–thaw, neutron reflection, protein aggregation, stress tolerance, Adsorption, Air, Animals, Arabidopsis Proteins, Biophysical Phenomena, Citrate (si)-Synthase, Cryoprotective Agents, Freezing, Helminth Proteins, Intrinsically Disordered Proteins, Neutron Diffraction, Protein Aggregates, Protein Folding, Protein Stability, Recombinant Proteins, Rhabditida, Scattering, Small Angle, Stress, Physiological, Swine, Water

Journal Title

Biochemical Journal

Conference Name

Journal ISSN

1470-8728
1470-8728

Volume Title

476

Publisher

Portland Press, Ltd.
Sponsorship
European Research Council (233232)
Canadian Research Council for PhD studentship + ERC grant