Abstract
Effects of the dehydration rate and the co-existing salts were investigated on the conformational structure of a LEA protein from P. vanderplanki, PvLEA2, which is composed of 180 amino acid residues, with a molecular weight of 20.6 kDa. The aqueous solution of the desalted pure LEA protein at 1mg/ml was vaporized at a constant rate in an environment with a given relative humidity (RH) kept constant. The resulting LEA protein with the residual water content being as low as 3 wt% had the content of a-helical structure at ca. 60% relative to the whole, except for the case of drying at RH = 98% which yielded ca 50% content of a-helical structure of the dehydrated LEA protein. The conformational structure of the dried LEA protein depended on the kinds of co-existing salts, being predominantly a-helical and 6-sheet structures in the presence of NaCl and CaCl_2, respectively. These findings suggest that it is controversial to apply the ion-sequestration mechanism to the relationship among the dehydrated LEA protein and all kinds of ionic species.
