Biochemical characterization of the Arabidopsis KS-type dehydrin protein, whose gene expression is constitutively abundant rather than stress dependent
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Dehydrins are known as plant stress-responsive genes. Arabidopsis thaliana has 10 dehydrin genes. Among them, one of the highly expressed genes is a KS-type dehydrin (At1g54410). However, the gene product, which is a histidine-rich dehydrin whose molecular mass is 11 kDa (AtHIRD11), has not been studied. Thus, we report the biochemical characterization of the AtHIRD11 protein. Although the AtHIRD11 protein was detected in all organs of Arabidopsis, the bolting stem and the flower showed higher accumulation than the other organs, with the AtHIRD11 protein detected in the cambial zone of the stem vasculature. Most of the AtHIRD11 protein was found to be a bound form. The bound AtHIRD11 was solubilized by 1 M NaCl solution. The extracted AtHIRD11 was retained in immobilized metal-affinity chromatography, and eluted by an imidazole gradient. The native AtHIRD11 prepared from Arabidopsis was partially phosphorylated, but further phosphorylated by casein kinase 2 in vitro. Metal-binding assays indicated that Zn2+ may be the best metal for AtHIRD11 binding. These results suggest that AtHIRD11 is a metal-binding dehydrin that shows a house-keeping expression in Arabidopsis.
KeywordsArabidopsisthaliana Dehydrin Late embryogenesis abundant proteins Metal binding
Arabidopsisthaliana histidine-rich dehydrin whose molecular mass is 11 kDa
Casein kinase 2
Two-dimensional polyacrylamide gel electrophoresis
Expressed sequence tag
Immobilized metal affinity chromatography
Polymerase chain reaction
Reverse transcription-polymerase chain reaction
Shrimp alkaline phosphatase
Sodium dodecyl sulfate
SDS-polyacrylamide gel electrophoresis
This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan (19380182).