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Functional dissection of Hydrophilins during in vitro freeze protection
Author(s) -
REYES JOSÉ L.,
CAMPOS FRANCISCO,
WEI HUI,
ARORA RAJEEV,
YANG YONGIL,
KARLSON DALE T.,
COVARRUBIAS ALEJANDRA A.
Publication year - 2008
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2008.01879.x
Subject(s) - lactate dehydrogenase , in vitro , enzyme , enzyme assay , biochemistry , chemistry , biophysics , fluorophore , amino acid , microbiology and biotechnology , biology , fluorescence , physics , quantum mechanics
In plants, Late Embryogenesis Abundant (LEA) proteins typically accumulate in response to low water availability conditions imposed during development or by the environment. Analogous proteins in other organisms are induced when exposed to stress conditions. Most of this diverse set of proteins can be grouped according to properties such as high hydrophilicity and high content of glycine or other small amino acids in what we have termed hydrophilins. Previously, we showed that hydrophilins protect enzyme activities in vitro from low water availability effects. Here, we demonstrate that hydrophilins can also protect enzyme activities from the adverse effects induced by freeze–thaw cycles in vitro . We monitored conformational changes induced by freeze–thaw on the enzyme lactate dehydrogenase (LDH) using the fluorophore 1‐anilinonaphthalene‐8‐sulfonate (ANS). Hydrophilin addition prevents enzyme inactivation and this effect is reflected in changes in the ANS‐fluorescence levels determined for LDH. We further show that for selected plant hydrophilins, removal of certain conserved domains affects their protecting capabilities. Thus, we propose that hydrophilins, and in particular specific protein domains, have a role in protecting cell components from the adverse effects caused by low water availability such as those present during freezing conditions by preventing deleterious changes in protein secondary and tertiary structure.