Protein-water and protein-buffer interactions in the aqueous solution of an intrinsically unstructured plant dehydrin: NMR intensity and DSC aspects

¹ Institute of Enzymology, Hungarian Academy of Sciences
² Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Budapest

^* To whom correspondence should be addressed. E-mail: tompa{at}enzim.hu.

Submitted on March 8, 2006
Revised on March 30, 2006
Accepted on 1 June 2006

	Abstract

Proton NMR intensity and differential scanning calorimetry (DSC) measurements were carried out on an intrinsically unstructured late embryogenesis abundant (LEA) protein, ERD10, the globular BSA and various buffer solutions to characterise water- and ion binding of proteins by this novel combination of experimental approaches. By quantifying the number of hydrate 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 it can also bind a large amount of charged solute ions. In accord, dehydration stress function of this protein probably results form its simultaneous action of retaining water in the drying cells and preventing adverse increase in ionic strength, thus countering deleterious effects, such as protein denaturation.

Key Words: NMR relaxation, differential scanning calorimetry, ion sequestration, protein disorder, protein-water interaction, unstructured protein

This article has been cited by other articles:

				D. Kovacs, E. Kalmar, Z. Torok, and P. Tompa Chaperone Activity of ERD10 and ERD14, Two Disordered Stress-Related Plant Proteins Plant Physiology, May 1, 2008; 147(1): 381 - 390. [Abstract] [Full Text] [PDF]