Functional studies of soybean (Glycine max L.) seed LEA proteins GmPM6, GmPM11, and GmPM30 by CD and FTIR spectroscopy

The protein and mRNA levels of late embryogenesis abundant (LEA) genes may be linked to osmotic stresses. Here, we characterized three soybean hydrophilic LEA proteins – GmPM11 (LEA I), GmPM6 (LEA II), and GmPM30 (LEA III) – by circular dichroism and Fourier transform infrared spectroscopy. Structural analysis revealed that the LEA proteins adopted high amounts of disordered conformations in solution and underwent conformational changes with hydrophobicity and desiccation induction. Macromolecular interaction studies revealed that the GmPM proteins interact with non-reducing sugars and phospholipids. GmPM6 and GmPM30 but not GmPM11 could prevent beta-aggregation of poly-l-lysine after slow drying. We discuss the possible functions of hydrophilic LEA proteins in maturing seeds.

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► The biophysical features of three soybean LEA proteins are characterized.
► The dehydrated LEA proteins adopt defined secondary structures.
► Dehydration rate can affect the proportions of defined secondary structures.
► The dehydrated LEA proteins can interact with other macromolecules.
► LEA 1 proteins are not a molecular chaperone after drying.