Premium
Folding of intrinsically disordered plant LEA proteins is driven by glycerol‐induced crowding and the presence of membranes
Author(s) -
Bremer Anne,
Wolff Martin,
Thalhammer Anja,
Hincha Dirk K.
Publication year - 2017
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.14023
Subject(s) - folding (dsp implementation) , chemistry , glycerol , biophysics , protein folding , membrane , biochemistry , membrane protein , crystallography , biology , engineering , electrical engineering
Late embryogenesis abundant ( LEA ) proteins are related to cellular dehydration tolerance. Most LEA proteins are predicted to have no stable secondary structure in solution, i.e., to be intrinsically disordered proteins ( IDP s), but they may acquire α‐helical structure upon drying. In the model plant Arabidopsis thaliana , the LEA proteins COR 15A and COR 15B are highly induced upon cold treatment and are necessary for the plants to attain full freezing tolerance. Freezing leads to increased intracellular crowding due to dehydration by extracellular ice crystals. In vitro , crowding by high glycerol concentrations induced partial folding of COR 15 proteins. Here, we have extended these investigations to two related proteins, LEA 11 and LEA 25. LEA 25 is much longer than LEA 11 and COR 15A, but shares a conserved central sequence domain with the other two proteins. We have created two truncated versions of LEA 25 (2H and 4H) to elucidate the structural and functional significance of this domain. Light scattering and CD spectroscopy showed that all five proteins were largely unstructured and monomeric in dilute solution. They folded in the presence of increasing concentrations of trifluoroethanol and glycerol. Additional folding was observed in the presence of glycerol and membranes. Fourier transform infra red spectroscopy revealed an interaction of the LEA proteins with membranes in the dry state leading to a depression in the gel to liquid‐crystalline phase transition temperature. Liposome stability assays revealed a cryoprotective function of the proteins. The C‐ and N‐terminal extensions of LEA 25 were important in cryoprotection, as the central domain itself (2H, 4H) only provided a low level of protection.