title: Structural transitions in the intrinsically disordered plant dehydration stress protein LEA7 upon drying are modulated by the presence of membranes.
abstract: Dehydration stress-related late embryogenesis abundant (LEA) proteins have been found in plants, invertebrates and bacteria. Most LEA proteins are unstructured in solution, but some fold into amphipathic α-helices during drying. The Pfam LEA_4 (Group 3) protein LEA7 from the higher plant Arabidopsis thaliana was predicted to be 87% α-helical, while CD spectroscopy showed it to be largely unstructured in solution and only 35% α-helical in the dry state. However, the dry protein contained 15% β-sheets. FTIR spectroscopy revealed the β-sheets to be largely due to aggregation. β-Sheet content was reduced and α-helix content increased when LEA7 was dried in the presence of liposomes with secondary structure apparently influenced by lipid composition. Secondary structure was also affected by the presence of membranes in the fully hydrated state. A temperature-induced increase in the flexibility of the dry protein was also only observed in the presence of membranes. Functional interactions of LEA7 with membranes in the dry state were indicated by its influence on the thermotropic phase transitions of the lipids and interactions with the lipid headgroup phosphates.
authors: Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany.
authors: Antoaneta V
authors: AV
authors: Popova
authors: Michaela
authors: M
authors: Hundertmark
authors: Robert
authors: R
authors: Seckler
authors: Dirk K
authors: DK
authors: Hincha
mesh_terms: D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics; D002462:Cell Membrane / Q000737:chemistry; D002942:Circular Dichroism; D003890:Desiccation; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D029681:Arabidopsis Proteins; D011994:Recombinant Proteins