Protein-water and protein-buffer interactions in the aqueous solution of an intrinsically unstructured plant dehydrin: NMR intensity and DSC aspects.
Proton NMR intensity and differential scanning calorimetry measurements were carried out on an intrinsically unstructured late embryogenesis abundant protein, ERD10, the globular BSA, and various buffer solutions to characterize water and ion binding of proteins by this novel combination of experimental approaches. By quantifying the number of hydration water molecules, the results demonstrate the interaction between the protein and NaCl and between buffer and NaCl on a microscopic level. The findings overall provide direct evidence that the intrinsically unstructured ERD10 not only has a high hydration capacity but can also bind a large amount of charged solute ions. In accord, the dehydration stress function of this protein probably results from its simultaneous action of retaining water in the drying cells and preventing an adverse increase in ionic strength, thus countering deleterious effects such as protein denaturation.
Tompa
P
P
Institute of Enzymology, Biological Research Center, and Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, H-1518 Budapest, Hungary. tompa@enzim.hu
Bánki
P
P
Bokor
M
M
Kamasa
P
P
Kovács
D
D
Lasanda
G
G
Tompa
K
K
D029681:Arabidopsis Proteins / Q000737:chemistry*; D002021:Buffers; D002152:Calorimetry, Differential Scanning; D019906:Nuclear Magnetic Resonance, Biomolecular; D010940:Plant Proteins / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D014867:Water / Q000737:chemistry*
D029681:Arabidopsis Proteins; D002021:Buffers; C089004:ERD10 protein, Arabidopsis; D010940:Plant Proteins; D014867:Water; C070556:dehydrin proteins, plant; D012710:Serum Albumin, Bovine; D012965:Sodium Chloride