Difference between revisions of "Phosphatase Subfamily Acr2"

Revision as of 17:26, 27 May 2014

Phosphatase Classification: Superfamily Cys-based II: Family CDC25: Subfamily Acr2

Prokaryotes and eukaryotes use arsenate reductases of distinct folds. E. coli uses ArsC, which belongs to Superfamily Cys-based III, the same as LMWPTP and SSU72. Eukaryotes, particularly fungi, plants and protists, may use ACR2 which have the same fold as CDC25 [1]. However, knocking out ACR2 does not affect arsenic redox status in Arabidopsis thaliana and Saccharomyces cerevisiae , which implies the existence of other arsenate reductase(s) in plants and yeast [2].

Arc2 in eukaryotes

Saccharomyces cerevisiae. Overexpressed in E. coli, ARR2, the ACR2 gene of Saccharomyces cerevisiae, was shown to exhibit arsenate reductase activity and complement the arsenate-sensitive phenotype of an ArsC deletion in E. coli [1, 3, 4]. The Cx5R motif is required for its catalytic activity as arsenate reductase [5].

Arabidopsis thaliana. Acr2 of Arabidopsis thaliana was initially characterized as a phosphatase, given the evidences: i) protein structure solved by NMR [6], ii) recombinant expression in E. coli shows tyrosine phosphatase activity towards artificial substrate [7], and iii) overexpression in fission yeast function suggests it is a mitotic accelerator [8]. It has been suggested to play a role in arsenate reduction [9, 10, 11]. However, knocking out ACR2 does not affect arsenic redox status in Arabidopsis thaliana and Saccharomyces cerevisiae [2].

Oryza sativa (rice). Rice has two Acr2s, which can complement the arsenate-sensitive phenotype of an ArsC deletion in E. coli at different levels[12]. The two genes not only reduce arsenate to arsenite in vitro, but also exhibit phosphatase activity. Mutagenesis of cysteine residues in the catalytic motif CX5R led to nearly complete loss of both phosphatase and arsenate reductase activities [12].

Pteris vittata (fern). The ACR2 of "Pteris vittata" (PvACR2) can suppress the arsenate sensitivity and arsenic hyperaccumulation phenotypes of yeast (Saccharomyces cerevisiae) lacking the arsenate reductase gene ACR2 [11, 13]. However, PvACR2 is unique in that the arginine of catalytic motif Cx5R, previously shown to be essential for phosphatase and reductase activity, is replaced with a serine.

Chlamydomonas reinhardtii (green alga). Chlamydomonas reinhardtii has two Acr2s. One of them complement the arsenate-sensitive phenotype of an ArsC deletion in E. coli [14].

Reference

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2. Error fetching PMID 22879969: [atha-ar-12]
3. Error fetching PMID 9812373: [yeast98]
4. Error fetching PMID 10801893: [yeast00]
5. Error fetching PMID 11461905: [yeast01]
6. Error fetching PMID 15329414: [atha-phosphatase-04]
7. Error fetching PMID 15329414: [atha-phosphatase-04b]
8. Error fetching PMID 15720653: [atha-phosphatase-05]
9. Error fetching PMID 16507083: [atha-ar-06]
10. Error fetching PMID 16567632: [atha-ar-06b]
11. Error fetching PMID 15834011: [fern05]
12. Error fetching PMID 17388894: [duan-07]
13. Error fetching PMID 16766666: [fern06]
14. Error fetching PMID 22125913: [green-alga-11]
15. Error fetching PMID 16949857: [Boudolf06]