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A CDC25 homologue from rice functions as an arsenate reductase
Author(s) -
Duan GuiLan,
Zhou Yao,
Tong YiPing,
Mukhopadhyay Rita,
Rosen Barry P.,
Zhu YongGuan
Publication year - 2007
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2007.02009.x
Subject(s) - arsenate , arsenite , saccharomyces cerevisiae , complementation , biology , biochemistry , yeast , gene , cdc25 , arsenic , microbiology and biotechnology , chemistry , phenotype , cyclin dependent kinase 1 , organic chemistry , cell cycle
Summary• Enzymatic reduction of arsenate to arsenite is the first step in arsenate metabolism in all organisms studied. The rice genome contains two ACR2‐like genes, OsACR2.1 and OsACR2.2 , which may be involved in regulating arsenic metabolism in rice. • Here, we cloned both OsACR2 genes and expressed them in an Escherichia coli strain in which the arsC gene was deleted and in a yeast ( Saccharomyces cerevisiae ) strain with a disrupted ACR2 gene. OsACR2.1 complemented the arsenate hypersensitive phenotype of E. coli and yeast. OsACR2.2 showed much less ability to complement. • The gene products were purified and demonstrated to reduce arsenate to arsenite in vitro , and both exhibited phosphatase activity. In agreement with the complementation results, OsACR2.1 exhibited higher reductase activity than OsACR2.2 . Mutagenesis of cysteine residues in the putative active site HC(X) 5 R motif led to nearly complete loss of both phosphatase and arsenate reductase activities. • In planta expression of OsACR2.1 increased dramatically after exposure to arsenate. OsACR2.2 was observed only in roots following arsenate exposure, and its expression was less than OsACR2.1 .