Water and protein dynamics in protein - Water mixtures over wide ranges of composition

Author

Kyritsis, A. ; Panagopoulou, A. ; Pissis, P. ; Serra, R. S i ; Ribelles, J. L Gómez ; Shinyashiki, N.

Author_Institution

Dept. of Phys., Nat. Tech. Univ. of Athens, Athens, Greece

fYear

2011

fDate

28-31 Aug. 2011

Firstpage

49

Lastpage

50

Abstract

In this paper, glass transition and water and protein dynamics were studied in water mixtures of two globular proteins, lysozyme and BSA, by DSC, DRS and TSDC measurements. DSC measurements were used for the study of crystallization and melting phenomena of absorbed water. The noncrystallized water has been determined to be about 0.20 and 0.24 for Lysozyme and BSA, respectively, independent on h_w. Dielectric measurements reveal the α relaxation process associated with the glass transition of the hydrated proteins for both systems, in agreement with DSC results. For water fractions where no crystallization of water occurs during cooling our results shown a strong plasticization of T_g. Splitting of the the α relaxation process, observed for h_w >; 0.20, is maybe due to microphase separation occurred on both hydrated proteins at that hydration levels.

Keywords

biochemistry; crystallisation; differential scanning calorimetry; enzymes; glass transition; melting; molecular biophysics; phase separation; solvation; sorption; water; α relaxation process; BSA; DRS; DSC; H₂O; TSDC; absorbed water; cooling; crystallization; dielectric measurement; glass transition; globular proteins; hydrated proteins; lysozyme; melting phenomena; microphase separation; noncrystallized water; plasticization; water mixtures; water-protein dynamics; Glass; Heating; Proteins;

fLanguage

English

Publisher

ieee

Conference_Titel

Electrets (ISE), 2011 14th International Symposium on

Conference_Location

Montpellier

ISSN

2153-3253

Print_ISBN

978-1-4577-1023-0

Type

conf

DOI

10.1109/ISE.2011.6084976

Filename

6084976