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Document Type

Article

Publication Date

8-14-2014

Abstract

Group 3 late embryogenesis abundant (LEA) proteins are highly

hydrophilic, and their expression is associated with desiccation

tolerance in both plants and animals. Here we show that two

LEA proteins from embryos of Artemia franciscana, AfrLEA2

and AfrLEA3m, are intrinsically disordered in solution but

upon desiccation gain secondary structure, as measured by circular

dichroism. Trifluoroethanol and sodium dodecyl sulfate

are both shown to induce a-helical structure in AfrLEA2 and

AfrLEA3m. Bioinformatic predictions of secondary-structure

content for both proteins correspond most closely to conformations

measured in the dry state. Because some LEA proteins

afford protection to desiccation-sensitive proteins during drying

and subsequent rehydration, we tested for this capacity in

AfrLEA2 and AfrLEA3m. The protective capacities vary, depending

on the target enzyme. For the cytoplasmic enzyme

lactate dehydrogenase, neither AfrLEA2 nor AfrLEA3m, with

or without trehalose present, was able to afford protection better

than that provided by bovine serum albumin (BSA) under

the same conditions. However, for another cytoplasmic enzyme,

phosphofructokinase, both AfrLEA2 and AfrLEA3m in the

presence of trehalose were able to afford protection far greater

than that provided by BSA with trehalose. Finally, for the mitochondrial

enzyme citrate synthase, 400-mg/mL AfrLEA3m

without trehalose provided significantly more protection than

the same concentration of either AfrLEA2 or BSA.

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